Fabio Cavaliere | Università degli Studi di Genova (original) (raw)

Papers by Fabio Cavaliere

Research paper thumbnail of Charge Oscillations in Quantum Spin Hall Constrictions

Research paper thumbnail of A Short Review of One-Dimensional Wigner Crystallization

Crystals

The simplest possible structural transition that an electronic system can undergo is Wigner cryst... more The simplest possible structural transition that an electronic system can undergo is Wigner crystallization. The aim of this short review is to discuss the main aspects of three recent experimets on the one-dimensional Wigner molecule, starting from scratch. To achieve this task, the Luttinger liquid theory of weakly and strongly interacting fermions is briefly addressed, together with the basic properties of carbon nanotubes that are required. Then, the most relevant properties of Wigner molecules are addressed, and finally the experiments are described. The main physical points that are addressed are the suppression of the energy scales related to the spin and isospin sectors of the Hamiltonian, and the peculiar structure that the electron density acquires in the Wigner molecule regime.

Research paper thumbnail of Correlation functions for the detection of Wigner molecules in a one-channel Luttinger liquid quantum dot

EPL (Europhysics Letters)

In one-channel, finite-size Luttinger one-dimensional quantum dots, both Friedel oscillations and... more In one-channel, finite-size Luttinger one-dimensional quantum dots, both Friedel oscillations and Wigner correlations induce oscillations in the electron density with the same wavelength, pinned at the same position. Therefore, observing such a property does not provide any hint about the formation of a Wigner molecule when electrons interact strongly and other tools must be employed to assess the formation of such correlated states. We compare here the behavior of three different correlation functions and demonstrate that the integrated two point correlation function, which represents the probability density of finding two particles at a given distance, is the only faithful estimator for the formation of a correlated Wigner molecule.

Research paper thumbnail of Negative conductance patterns of quantum dots: experiment and theory

New Journal of Physics

Experimental results for the sequential transport through a lateral quantum dot in a perpendicula... more Experimental results for the sequential transport through a lateral quantum dot in a perpendicular magnetic field are compared with theory. Regular patterns of negative differential conductances are observed in the nonlinear regime. We attempt to reproduce theoretically these patterns in a simplified model which captures the essential features of the experimental system. Orbital and spin effects are treated in terms of the Fock-Darwin model. The transport properties are described by employing a master equation with tunable tunnelling and relaxation rates. We show that the essential physics underlying the experiment can be described within our approach if the timescales of the different transport channels are well separated.

Research paper thumbnail of Crystallization of fractional charges in a strongly interacting quasihelical quantum dot

Physical Review B, 2015

The ground-state electron density of a one-dimensional spin-orbit coupled quantum dot with a Zeem... more The ground-state electron density of a one-dimensional spin-orbit coupled quantum dot with a Zeeman term and strong electron interaction is studied at the fractional helical liquid points. We show that at fractional filling factors ν = (2n + 1) −1 (with n a non-negative integer) the density oscillates with N0/ν peaks. For n ≥ 1 a number of peaks larger than the number of electrons N0 suggests that a crystal of fractional quasi-particles with charge νe (with e the electron charge) occurs. The reported effect is amenable of verification via transport measurements in charged AFM-coupled dot.

Research paper thumbnail of Current noise as a probe for Wigner molecules

Journal of Physics: Condensed Matter, 2015

ABSTRACT

Research paper thumbnail of Anomalous Friedel oscillations in a quasihelical quantum dot

Physical Review B, 2015

The charge and spin patterns of a quantum dot embedded into a spin-orbit coupled quantum wire sub... more The charge and spin patterns of a quantum dot embedded into a spin-orbit coupled quantum wire subject to a magnetic field are investigated. A Luttinger liquid theory is developed, taking into account open boundaries and finite magnetic field. In the quasi-helical regime, when spin-orbit effects dominate over the Zeeman interaction, peculiar states develop at the Fermi surface of the dot. Anomalous Friedel oscillations with twice the expected wavelength develop in the wavefunction of collective excitations of such states, accompanied by peculiar spin patterns in their magnetization. Both effects are analyzed in detail and shown possible to be probed in transport experiments. The stability against electron interactions and magnetic field is investigated. We also discuss how signatures of such states survive in the total charge and spin densities.

Research paper thumbnail of zur Erlangung des Doktorgrades des Fachbereichs Physik der Universitat Hamburg

... EFFECT Dissertation zur Erlangung des Doktorgrades des Fachbereichs Physik der Universit¨at H... more ... EFFECT Dissertation zur Erlangung des Doktorgrades des Fachbereichs Physik der Universit¨at Hamburg vorgelegt von EROS MARIANI aus GENOVA (ITALIEN) Hamburg 2003 Page 2. Gutachter der Dissertation: 1. Prof. Dr. Bernhard Kramer 2. Prof. Dr. Franco Napoli ...

Research paper thumbnail of Wigner oscillations in strongly correlated carbon nanotube quantum dots

The European Physical Journal Plus, 2014

ABSTRACT The competition between Friedel and Wigner oscillations in the density of strongly inter... more ABSTRACT The competition between Friedel and Wigner oscillations in the density of strongly interacting carbon nanotubes is inspected within the Luttinger liquid picture. The power laws of the low temperature density oscillations are different from the usual case of quantum dots defined in quantum wires. Temperature plays an important role in the visibility of Wigner oscillations: both Friedel and Wigner oscillations are suppressed, but Friedel oscillations are suppressed at much lower temperature, signalling the incipience of spin-incoherent Luttinger liquid state.

Research paper thumbnail of Transport properties of quantum wires

Solid State Communications, 2004

Electron transport in Luttinger liquids connected by tunnel barriers is reviewed. The non-analyti... more Electron transport in Luttinger liquids connected by tunnel barriers is reviewed. The non-analytic temperature behavior of the conductance of a single tunnel barrier is derived. An overview of charge and spin transport properties through a one-dimensional quantum dot ...

Research paper thumbnail of Coherent properties of nanoelectromechanical systems

Physical Review B, 2011

We study the properties of a nano-electromechanical system in the coherent regime, where the elec... more We study the properties of a nano-electromechanical system in the coherent regime, where the electronic and vibrational time scales are of the same order. Employing a master equation approach, we obtain the stationary reduced density matrix retaining the coherences between vibrational states. Depending on the system parameters, two regimes are identified, characterized by either (i) an effective thermal state with a temperature lower than that of the environment or (ii) strong coherent effects. A marked cooling of the vibrational degree of freedom is observed with a suppression of the vibron Fano factor down to sub-Poissonian values and a reduction of the position and momentum quadratures.

Research paper thumbnail of Spin effects in transport through non-Fermi-liquid quantum dots

Physical Review B, 2004

The current-voltage characteristic of a one dimensional quantum dot connected via tunnel barriers... more The current-voltage characteristic of a one dimensional quantum dot connected via tunnel barriers to interacting leads is calculated in the region of sequential tunneling. The spin of the electrons is taken into account. Non-Fermi liquid correlations implying spin-charge separation are assumed to be present in the dot and in the leads. It is found that the energetic distance of the peaks in the linear conductance shows a spin-induced parity effect at zero temperature T. The temperature dependence of the positions of the peaks depends on the non-Fermi liquid nature of the system. For non-symmetric tunnel barriers negative differential conductances are predicted, which are related to the participation in the transport of collective states in the quantum dot with larger spins. Without spin-charge separation the negative differential conductances do not occur. Taking into account spin relaxation destroys the spin-induced conductance features. The possibility of observing in experiment the predicted effects are briefly discussed.

Research paper thumbnail of Shot noise in charge and magnetization currents of a quantum ring

Physical Review B, 2005

The shot noise in a quantum ring, connected to leads, is studied in the presence of electron inte... more The shot noise in a quantum ring, connected to leads, is studied in the presence of electron interactions in the sequential tunneling regime. Two qualitatively different noise correlations with distinctly different behaviors are identified and studied in a large range of parameters. Noise in the total current is due to the discreteness of the electron charge and can become super-Poissonian as result of electron interaction. The noise in the magnetization current is comparatively insensitive to the interaction but can be greatly enhanced if population inversion of the angular states is assumed. The characteristic time scales are studied by a Monte-Carlo simulation.

Research paper thumbnail of Negative differential conductance induced by electronic correlation in a double quantum dot molecule

Physical Review B, 2008

Spin-charge states of correlated electrons in a one-dimensional quantum dot attached to interacti... more Spin-charge states of correlated electrons in a one-dimensional quantum dot attached to interacting leads are studied in the non-linear transport regime. With non-symmetric tunnel barriers, regions of negative differential conductance induced by spin-charge separation are found. They are due to a correlation-induced trapping of higher-spin states without magnetic field, and associated with a strong increase in the fluctuations of the electron spin.

Research paper thumbnail of Magnetic ac control of the spin textures in a helical Luttinger liquid

Physical Review B, 2014

We demonstrate the possibility to induce and control peculiar spin textures in a helical Luttinge... more We demonstrate the possibility to induce and control peculiar spin textures in a helical Luttinger liquid, by means of a time-dependent magnetic scatterer. The presence of a perturbation that breaks the time-reversal symmetry opens a gap in the spectrum, inducing single-particle backscattering and a peculiar spin response. We show that in the weak backscattering regime asymmetric spin textures emerge at the left and right side of the scatterer, whose spatial oscillations are controlled by the ratio between the magnetization frequency and the Fermi energy and by the electron interaction. This peculiar spin response marks a strong difference between helical and non-helical liquids, which are expected to produce symmetric spin textures even in the AC regime.

Research paper thumbnail of Coulomb blockade microscopy of spin-density oscillations and fractional charge in quantum spin Hall dots

Physical Review B, 2013

We evaluate the spin-density oscillations arising in quantum spin Hall quantum dots created via t... more We evaluate the spin-density oscillations arising in quantum spin Hall quantum dots created via two localized magnetic barriers. The combined presence of magnetic barriers and spin-momentum locking, the hallmark of topological insulators, leads to peculiar phenomena: A half-integer charge is trapped in the dot for antiparallel magnetization of the barriers, and oscillations appear in the in-plane spin density, which are enhanced in the presence of electron interactions. Furthermore, we show that the number of these oscillations is determined by the number of particles inside the dot so that the presence or absence of the fractional charge can be deduced from the in-plane spin density. We show that, when the dot is coupled with a magnetized tip, the spatial shift induced in the chemical potential allows for probing these peculiar features.

Research paper thumbnail of Signatures of Wigner correlations in the conductance of a one-dimensional quantum dot coupled to an AFM tip

Physical Review B, 2012

The transport properties of an interacting one-dimensional quantum dot capacitively coupled to an... more The transport properties of an interacting one-dimensional quantum dot capacitively coupled to an atomic force microscope probe are investigated. The dot is described within a Luttinger liquid framework which captures both Friedel and Wigner oscillations. In the linear regime, we demonstrate that both the conductance peak position and height oscillate as the tip is scanned along the dot. A pronounced beating pattern in the conductance maximum is observed, connected to the oscillations of the electron density. Signatures of the effects induced by a Wigner molecule are clearly identified and their stability against the strength of Coulomb interactions are analyzed. While the oscillations of the peak position due to Wigner get enhanced at strong interactions, the peak height modulations are suppressed as interactions grow. Oscillations due to Friedel, on the other hand, are robust against interaction.

Research paper thumbnail of Generating and controlling spin-polarized currents induced by a quantum spin Hall antidot

Physical Review B, 2013

We study an electrically-controlled quantum spin Hall antidot embedded in a two-dimensional topol... more We study an electrically-controlled quantum spin Hall antidot embedded in a two-dimensional topological insulating bar. Helical edge states around the antidot and along the edges of the bar are tunnel-coupled. The close connection between spin and chirality, typical of helical systems, allows to generate a spin-polarized current flowing across the bar. This current is studied as a function of the external voltages, by varying the asymmetry between the barriers. For asymmetric setups, a switching behavior of the spin current is observed as the bias is increased, both in the absence and in the presence of electron interactions. This device allows to generate and control the spin-polarized current by simple electrical means.

Research paper thumbnail of Spin-projected unrestricted Hartree-Fock ground states for harmonic quantum dots

Physical Review B, 2008

We report results for the ground state energies and wave functions obtained by projecting spatial... more We report results for the ground state energies and wave functions obtained by projecting spatially unrestricted Hartree Fock states to eigenstates of the total spin and the angular momentum for harmonic quantum dots with N ≤ 12 interacting electrons including a magnetic field. The ground states with the correct spatial and spin symmetries have lower energies than those obtained by the unrestricted method. The chemical potential as a function of a perpendicular magnetic field is obtained. Signature of an intrinsic spin blockade effect is found.

Research paper thumbnail of Suppression of the Fano factor in nanoelectromechanical systems

Physica E: Low-dimensional Systems and Nanostructures, 2008

We analyze the shot noise of a spin-degenerate electronic level coupled to an harmonic oscillator... more We analyze the shot noise of a spin-degenerate electronic level coupled to an harmonic oscillator in the presence of relaxation. We show that the electromechanical coupling can induce a suppression of the Fano factor below the value expected without phonons F= 59. ...

Research paper thumbnail of Charge Oscillations in Quantum Spin Hall Constrictions

Research paper thumbnail of A Short Review of One-Dimensional Wigner Crystallization

Crystals

The simplest possible structural transition that an electronic system can undergo is Wigner cryst... more The simplest possible structural transition that an electronic system can undergo is Wigner crystallization. The aim of this short review is to discuss the main aspects of three recent experimets on the one-dimensional Wigner molecule, starting from scratch. To achieve this task, the Luttinger liquid theory of weakly and strongly interacting fermions is briefly addressed, together with the basic properties of carbon nanotubes that are required. Then, the most relevant properties of Wigner molecules are addressed, and finally the experiments are described. The main physical points that are addressed are the suppression of the energy scales related to the spin and isospin sectors of the Hamiltonian, and the peculiar structure that the electron density acquires in the Wigner molecule regime.

Research paper thumbnail of Correlation functions for the detection of Wigner molecules in a one-channel Luttinger liquid quantum dot

EPL (Europhysics Letters)

In one-channel, finite-size Luttinger one-dimensional quantum dots, both Friedel oscillations and... more In one-channel, finite-size Luttinger one-dimensional quantum dots, both Friedel oscillations and Wigner correlations induce oscillations in the electron density with the same wavelength, pinned at the same position. Therefore, observing such a property does not provide any hint about the formation of a Wigner molecule when electrons interact strongly and other tools must be employed to assess the formation of such correlated states. We compare here the behavior of three different correlation functions and demonstrate that the integrated two point correlation function, which represents the probability density of finding two particles at a given distance, is the only faithful estimator for the formation of a correlated Wigner molecule.

Research paper thumbnail of Negative conductance patterns of quantum dots: experiment and theory

New Journal of Physics

Experimental results for the sequential transport through a lateral quantum dot in a perpendicula... more Experimental results for the sequential transport through a lateral quantum dot in a perpendicular magnetic field are compared with theory. Regular patterns of negative differential conductances are observed in the nonlinear regime. We attempt to reproduce theoretically these patterns in a simplified model which captures the essential features of the experimental system. Orbital and spin effects are treated in terms of the Fock-Darwin model. The transport properties are described by employing a master equation with tunable tunnelling and relaxation rates. We show that the essential physics underlying the experiment can be described within our approach if the timescales of the different transport channels are well separated.

Research paper thumbnail of Crystallization of fractional charges in a strongly interacting quasihelical quantum dot

Physical Review B, 2015

The ground-state electron density of a one-dimensional spin-orbit coupled quantum dot with a Zeem... more The ground-state electron density of a one-dimensional spin-orbit coupled quantum dot with a Zeeman term and strong electron interaction is studied at the fractional helical liquid points. We show that at fractional filling factors ν = (2n + 1) −1 (with n a non-negative integer) the density oscillates with N0/ν peaks. For n ≥ 1 a number of peaks larger than the number of electrons N0 suggests that a crystal of fractional quasi-particles with charge νe (with e the electron charge) occurs. The reported effect is amenable of verification via transport measurements in charged AFM-coupled dot.

Research paper thumbnail of Current noise as a probe for Wigner molecules

Journal of Physics: Condensed Matter, 2015

ABSTRACT

Research paper thumbnail of Anomalous Friedel oscillations in a quasihelical quantum dot

Physical Review B, 2015

The charge and spin patterns of a quantum dot embedded into a spin-orbit coupled quantum wire sub... more The charge and spin patterns of a quantum dot embedded into a spin-orbit coupled quantum wire subject to a magnetic field are investigated. A Luttinger liquid theory is developed, taking into account open boundaries and finite magnetic field. In the quasi-helical regime, when spin-orbit effects dominate over the Zeeman interaction, peculiar states develop at the Fermi surface of the dot. Anomalous Friedel oscillations with twice the expected wavelength develop in the wavefunction of collective excitations of such states, accompanied by peculiar spin patterns in their magnetization. Both effects are analyzed in detail and shown possible to be probed in transport experiments. The stability against electron interactions and magnetic field is investigated. We also discuss how signatures of such states survive in the total charge and spin densities.

Research paper thumbnail of zur Erlangung des Doktorgrades des Fachbereichs Physik der Universitat Hamburg

... EFFECT Dissertation zur Erlangung des Doktorgrades des Fachbereichs Physik der Universit¨at H... more ... EFFECT Dissertation zur Erlangung des Doktorgrades des Fachbereichs Physik der Universit¨at Hamburg vorgelegt von EROS MARIANI aus GENOVA (ITALIEN) Hamburg 2003 Page 2. Gutachter der Dissertation: 1. Prof. Dr. Bernhard Kramer 2. Prof. Dr. Franco Napoli ...

Research paper thumbnail of Wigner oscillations in strongly correlated carbon nanotube quantum dots

The European Physical Journal Plus, 2014

ABSTRACT The competition between Friedel and Wigner oscillations in the density of strongly inter... more ABSTRACT The competition between Friedel and Wigner oscillations in the density of strongly interacting carbon nanotubes is inspected within the Luttinger liquid picture. The power laws of the low temperature density oscillations are different from the usual case of quantum dots defined in quantum wires. Temperature plays an important role in the visibility of Wigner oscillations: both Friedel and Wigner oscillations are suppressed, but Friedel oscillations are suppressed at much lower temperature, signalling the incipience of spin-incoherent Luttinger liquid state.

Research paper thumbnail of Transport properties of quantum wires

Solid State Communications, 2004

Electron transport in Luttinger liquids connected by tunnel barriers is reviewed. The non-analyti... more Electron transport in Luttinger liquids connected by tunnel barriers is reviewed. The non-analytic temperature behavior of the conductance of a single tunnel barrier is derived. An overview of charge and spin transport properties through a one-dimensional quantum dot ...

Research paper thumbnail of Coherent properties of nanoelectromechanical systems

Physical Review B, 2011

We study the properties of a nano-electromechanical system in the coherent regime, where the elec... more We study the properties of a nano-electromechanical system in the coherent regime, where the electronic and vibrational time scales are of the same order. Employing a master equation approach, we obtain the stationary reduced density matrix retaining the coherences between vibrational states. Depending on the system parameters, two regimes are identified, characterized by either (i) an effective thermal state with a temperature lower than that of the environment or (ii) strong coherent effects. A marked cooling of the vibrational degree of freedom is observed with a suppression of the vibron Fano factor down to sub-Poissonian values and a reduction of the position and momentum quadratures.

Research paper thumbnail of Spin effects in transport through non-Fermi-liquid quantum dots

Physical Review B, 2004

The current-voltage characteristic of a one dimensional quantum dot connected via tunnel barriers... more The current-voltage characteristic of a one dimensional quantum dot connected via tunnel barriers to interacting leads is calculated in the region of sequential tunneling. The spin of the electrons is taken into account. Non-Fermi liquid correlations implying spin-charge separation are assumed to be present in the dot and in the leads. It is found that the energetic distance of the peaks in the linear conductance shows a spin-induced parity effect at zero temperature T. The temperature dependence of the positions of the peaks depends on the non-Fermi liquid nature of the system. For non-symmetric tunnel barriers negative differential conductances are predicted, which are related to the participation in the transport of collective states in the quantum dot with larger spins. Without spin-charge separation the negative differential conductances do not occur. Taking into account spin relaxation destroys the spin-induced conductance features. The possibility of observing in experiment the predicted effects are briefly discussed.

Research paper thumbnail of Shot noise in charge and magnetization currents of a quantum ring

Physical Review B, 2005

The shot noise in a quantum ring, connected to leads, is studied in the presence of electron inte... more The shot noise in a quantum ring, connected to leads, is studied in the presence of electron interactions in the sequential tunneling regime. Two qualitatively different noise correlations with distinctly different behaviors are identified and studied in a large range of parameters. Noise in the total current is due to the discreteness of the electron charge and can become super-Poissonian as result of electron interaction. The noise in the magnetization current is comparatively insensitive to the interaction but can be greatly enhanced if population inversion of the angular states is assumed. The characteristic time scales are studied by a Monte-Carlo simulation.

Research paper thumbnail of Negative differential conductance induced by electronic correlation in a double quantum dot molecule

Physical Review B, 2008

Spin-charge states of correlated electrons in a one-dimensional quantum dot attached to interacti... more Spin-charge states of correlated electrons in a one-dimensional quantum dot attached to interacting leads are studied in the non-linear transport regime. With non-symmetric tunnel barriers, regions of negative differential conductance induced by spin-charge separation are found. They are due to a correlation-induced trapping of higher-spin states without magnetic field, and associated with a strong increase in the fluctuations of the electron spin.

Research paper thumbnail of Magnetic ac control of the spin textures in a helical Luttinger liquid

Physical Review B, 2014

We demonstrate the possibility to induce and control peculiar spin textures in a helical Luttinge... more We demonstrate the possibility to induce and control peculiar spin textures in a helical Luttinger liquid, by means of a time-dependent magnetic scatterer. The presence of a perturbation that breaks the time-reversal symmetry opens a gap in the spectrum, inducing single-particle backscattering and a peculiar spin response. We show that in the weak backscattering regime asymmetric spin textures emerge at the left and right side of the scatterer, whose spatial oscillations are controlled by the ratio between the magnetization frequency and the Fermi energy and by the electron interaction. This peculiar spin response marks a strong difference between helical and non-helical liquids, which are expected to produce symmetric spin textures even in the AC regime.

Research paper thumbnail of Coulomb blockade microscopy of spin-density oscillations and fractional charge in quantum spin Hall dots

Physical Review B, 2013

We evaluate the spin-density oscillations arising in quantum spin Hall quantum dots created via t... more We evaluate the spin-density oscillations arising in quantum spin Hall quantum dots created via two localized magnetic barriers. The combined presence of magnetic barriers and spin-momentum locking, the hallmark of topological insulators, leads to peculiar phenomena: A half-integer charge is trapped in the dot for antiparallel magnetization of the barriers, and oscillations appear in the in-plane spin density, which are enhanced in the presence of electron interactions. Furthermore, we show that the number of these oscillations is determined by the number of particles inside the dot so that the presence or absence of the fractional charge can be deduced from the in-plane spin density. We show that, when the dot is coupled with a magnetized tip, the spatial shift induced in the chemical potential allows for probing these peculiar features.

Research paper thumbnail of Signatures of Wigner correlations in the conductance of a one-dimensional quantum dot coupled to an AFM tip

Physical Review B, 2012

The transport properties of an interacting one-dimensional quantum dot capacitively coupled to an... more The transport properties of an interacting one-dimensional quantum dot capacitively coupled to an atomic force microscope probe are investigated. The dot is described within a Luttinger liquid framework which captures both Friedel and Wigner oscillations. In the linear regime, we demonstrate that both the conductance peak position and height oscillate as the tip is scanned along the dot. A pronounced beating pattern in the conductance maximum is observed, connected to the oscillations of the electron density. Signatures of the effects induced by a Wigner molecule are clearly identified and their stability against the strength of Coulomb interactions are analyzed. While the oscillations of the peak position due to Wigner get enhanced at strong interactions, the peak height modulations are suppressed as interactions grow. Oscillations due to Friedel, on the other hand, are robust against interaction.

Research paper thumbnail of Generating and controlling spin-polarized currents induced by a quantum spin Hall antidot

Physical Review B, 2013

We study an electrically-controlled quantum spin Hall antidot embedded in a two-dimensional topol... more We study an electrically-controlled quantum spin Hall antidot embedded in a two-dimensional topological insulating bar. Helical edge states around the antidot and along the edges of the bar are tunnel-coupled. The close connection between spin and chirality, typical of helical systems, allows to generate a spin-polarized current flowing across the bar. This current is studied as a function of the external voltages, by varying the asymmetry between the barriers. For asymmetric setups, a switching behavior of the spin current is observed as the bias is increased, both in the absence and in the presence of electron interactions. This device allows to generate and control the spin-polarized current by simple electrical means.

Research paper thumbnail of Spin-projected unrestricted Hartree-Fock ground states for harmonic quantum dots

Physical Review B, 2008

We report results for the ground state energies and wave functions obtained by projecting spatial... more We report results for the ground state energies and wave functions obtained by projecting spatially unrestricted Hartree Fock states to eigenstates of the total spin and the angular momentum for harmonic quantum dots with N ≤ 12 interacting electrons including a magnetic field. The ground states with the correct spatial and spin symmetries have lower energies than those obtained by the unrestricted method. The chemical potential as a function of a perpendicular magnetic field is obtained. Signature of an intrinsic spin blockade effect is found.

Research paper thumbnail of Suppression of the Fano factor in nanoelectromechanical systems

Physica E: Low-dimensional Systems and Nanostructures, 2008

We analyze the shot noise of a spin-degenerate electronic level coupled to an harmonic oscillator... more We analyze the shot noise of a spin-degenerate electronic level coupled to an harmonic oscillator in the presence of relaxation. We show that the electromechanical coupling can induce a suppression of the Fano factor below the value expected without phonons F= 59. ...