A. Patanè - Academia.edu (original) (raw)

Papers by A. Patanè

Research paper thumbnail of Manipulating and Imaging the Shape of an Electronic Wave Function by Magnetotunneling Spectroscopy

Physical Review Letters, 2010

We measure the current due to electrons tunneling through the ground state of hydrogenic Si donor... more We measure the current due to electrons tunneling through the ground state of hydrogenic Si donors placed in a GaAs quantum well in the presence of a magnetic field tilted at an angle to the plane of the well. The component of B parallel to the direction of current compresses the donor wave function. By measuring the current as a function of the perpendicular component of B, we probe how the magnetocompression affects the spatial form of the wave function and observe directly the transition from Coulombic to magnetic confinement at high fields.

Research paper thumbnail of Manipulating and Imaging the Shape of an Electronic Wave Function by Magnetotunneling Spectroscopy

Physical Review Letters, 2010

We measure the current due to electrons tunneling through the ground state of hydrogenic Si donor... more We measure the current due to electrons tunneling through the ground state of hydrogenic Si donors placed in a GaAs quantum well in the presence of a magnetic field tilted at an angle to the plane of the well. The component of B parallel to the direction of current compresses the donor wave function. By measuring the current as a function of the perpendicular component of B, we probe how the magnetocompression affects the spatial form of the wave function and observe directly the transition from Coulombic to magnetic confinement at high fields.

Research paper thumbnail of Electron conduction in two-dimensional GaAs1-yNy channels

Physical Review B, 2004

... Rev. B 64, 113308 (2001). SR Kurtz, AA Allerman, CH Seager, RM Sieg, and ED Jones, Appl. Phys... more ... Rev. B 64, 113308 (2001). SR Kurtz, AA Allerman, CH Seager, RM Sieg, and ED Jones, Appl. Phys. Lett. ... Phys. Lett. 81, 3987 (2002) [SPIN][INSPEC][ADS][CAS]. XX Wang, CJ Martoff, and E. Kaczanowicz, Phys. Rev. B 51, 5402 (1995) [CAS]. ...

Research paper thumbnail of Miniband magneto-transport in GaAs/AlAs island superlattices

Physica E: Low-dimensional Systems and Nanostructures, 2002

ABSTRACT We study electron miniband magneto-transport in GaAs/AlAs superlattices with AlAs barrie... more ABSTRACT We study electron miniband magneto-transport in GaAs/AlAs superlattices with AlAs barriers of two monolayers. Here, the two-dimensional AlAs barrier comprises an in-plane distribution of AlAs islands. We use magneto-transport to probe both the rate and the anisotropy of the electron scattering associated with the islands.

Research paper thumbnail of Measuring the energy levels and wave functions in a single quantum dot

Physica E: Low-dimensional Systems and Nanostructures, 2002

ABSTRACT We use an array of gate electrodes to select an individual self-assembled quantum dot fr... more ABSTRACT We use an array of gate electrodes to select an individual self-assembled quantum dot from an ensemble. In combination with magneto-tunnelling spectroscopy, this allows us to measure the energy levels and wave functions associated with the ground and excited state of the selected quantum dot.

Research paper thumbnail of Transport properties of gated sub-micron mesas incorporating InAs self-assembled quantum dots that conduct near zero bias

Physica E: Low-dimensional Systems and Nanostructures, 2005

ABSTRACT We have fabricated multiple-gate vertical mesa transistors to investigate the Coulomb os... more ABSTRACT We have fabricated multiple-gate vertical mesa transistors to investigate the Coulomb oscillation and Coulomb diamond-like characteristics of a planar ensemble of self-assembled InAs quantum dots located in the central plane of a single 14nm Al0.2Ga0.8As tunnel barrier. The current–voltage characteristics are dominated by electron tunneling through the energy levels of just a few (∼10) dots. Since these dots are located at various distances from the mesa side walls, the dot energy levels up-shift at different rates when the gate-adjustable front of the depletion region spreads towards the center of the mesa. This results in Coulomb-diamond apexes with different gate voltage signatures.

Research paper thumbnail of Magneto-photoluminescence of stacked self-assembled InAs/GaAs quantum dots

Physica B: Condensed Matter, 2004

ABSTRACT We studied ten-fold stacked layers of self-assembled InAs/GaAs quantum dots by photolumi... more ABSTRACT We studied ten-fold stacked layers of self-assembled InAs/GaAs quantum dots by photoluminescence in pulsed magnetic fields. When the interlayer distance is reduced from 9.8 to , a doubling of the diamagnetic shift for a magnetic field perpendicular to the [001] direction reveals the onset of electron coupling between the dots in the stack. On reducing the interlayer distance to , a lower exciton effective mass is seen in addition to the coupling. For such a close stacking, the strain field in and around the dot is completely different from that of a single-layered structure. In particular, the strain inside the InAs dots in the stack is partially relaxed, causing the observed effect.

Research paper thumbnail of Strong Effect of Resonant Impurities on Landau-Level Quantization

Physical Review Letters - PHYS REV LETT, 2006

We investigate experimentally the effect of a random distribution of nitrogen (N) impurities on t... more We investigate experimentally the effect of a random distribution of nitrogen (N) impurities on the Landau-level spectrum of a GaAs quantum well. Our magnetotunneling study reveals complex and nonequally spaced Landau levels and a quenching of the Landau states at a well-defined bias and electron energy which is resonant with that of the N atoms. Analysis of the magnetic field dependence of the tunnel current into the Landau levels of the well also provides quantitative information about the nonresonant component of the N-related scattering potential.

Research paper thumbnail of Chaotic electron diffusion through stochastic webs enhances current flow in superlattices

Nature, 2004

IMBH via the process described above. So far, no bright X-ray source has been found in this cluster.

Research paper thumbnail of Fock-Darwin-Like Quantum Dot States Formed by Charged Mn Interstitial Ions

Physical Review Letters, 2008

We report a method of creating electrostatically induced quantum dots by thermal diffusion of int... more We report a method of creating electrostatically induced quantum dots by thermal diffusion of interstitial Mn ions out of a p-type (GaMn)As layer into the vicinity of a GaAs quantum well. This approach creates deep, approximately circular, and strongly confined dotlike potential minima in a large (200 microm) mesa diode structure without need for advanced lithography or electrostatic gating. Magnetotunneling spectroscopy of an individual dot reveals the symmetry of its electronic eigenfunctions and a rich energy level spectrum of Fock-Darwin-like states with an orbital angular momentum component |lz| from 0 to 11.

Research paper thumbnail of Strain relaxation in stacked InAs/GaAs quantum dots studied by Raman scattering

Applied Physics Letters, 2003

ABSTRACT We report a Raman scattering investigation of InAs vibrational modes in multiple layers ... more ABSTRACT We report a Raman scattering investigation of InAs vibrational modes in multiple layers of InAs self-assembled quantum dots in a GaAs matrix. The Raman peak associated with quantum-dot phonons shows a downward frequency shift as the interlayer spacing decreases. We attribute this frequency shift to the relaxation of the elastic strain in the stacked quantum-dot layers. From the phonon frequency shift, we estimate the magnitude of the strain in the quantum dot layers, which we relate to the energy of the photoluminescence emission of the dots. © 2003 American Institute of Physics.

Research paper thumbnail of Manipulating and Imaging the Shape of an Electronic Wave Function by Magnetotunneling Spectroscopy

Physical Review Letters, 2010

We measure the current due to electrons tunneling through the ground state of hydrogenic Si donor... more We measure the current due to electrons tunneling through the ground state of hydrogenic Si donors placed in a GaAs quantum well in the presence of a magnetic field tilted at an angle to the plane of the well. The component of B parallel to the direction of current compresses the donor wave function. By measuring the current as a function of the perpendicular component of B, we probe how the magnetocompression affects the spatial form of the wave function and observe directly the transition from Coulombic to magnetic confinement at high fields.

Research paper thumbnail of Manipulating and Imaging the Shape of an Electronic Wave Function by Magnetotunneling Spectroscopy

Physical Review Letters, 2010

We measure the current due to electrons tunneling through the ground state of hydrogenic Si donor... more We measure the current due to electrons tunneling through the ground state of hydrogenic Si donors placed in a GaAs quantum well in the presence of a magnetic field tilted at an angle to the plane of the well. The component of B parallel to the direction of current compresses the donor wave function. By measuring the current as a function of the perpendicular component of B, we probe how the magnetocompression affects the spatial form of the wave function and observe directly the transition from Coulombic to magnetic confinement at high fields.

Research paper thumbnail of Electron conduction in two-dimensional GaAs1-yNy channels

Physical Review B, 2004

... Rev. B 64, 113308 (2001). SR Kurtz, AA Allerman, CH Seager, RM Sieg, and ED Jones, Appl. Phys... more ... Rev. B 64, 113308 (2001). SR Kurtz, AA Allerman, CH Seager, RM Sieg, and ED Jones, Appl. Phys. Lett. ... Phys. Lett. 81, 3987 (2002) [SPIN][INSPEC][ADS][CAS]. XX Wang, CJ Martoff, and E. Kaczanowicz, Phys. Rev. B 51, 5402 (1995) [CAS]. ...

Research paper thumbnail of Miniband magneto-transport in GaAs/AlAs island superlattices

Physica E: Low-dimensional Systems and Nanostructures, 2002

ABSTRACT We study electron miniband magneto-transport in GaAs/AlAs superlattices with AlAs barrie... more ABSTRACT We study electron miniband magneto-transport in GaAs/AlAs superlattices with AlAs barriers of two monolayers. Here, the two-dimensional AlAs barrier comprises an in-plane distribution of AlAs islands. We use magneto-transport to probe both the rate and the anisotropy of the electron scattering associated with the islands.

Research paper thumbnail of Measuring the energy levels and wave functions in a single quantum dot

Physica E: Low-dimensional Systems and Nanostructures, 2002

ABSTRACT We use an array of gate electrodes to select an individual self-assembled quantum dot fr... more ABSTRACT We use an array of gate electrodes to select an individual self-assembled quantum dot from an ensemble. In combination with magneto-tunnelling spectroscopy, this allows us to measure the energy levels and wave functions associated with the ground and excited state of the selected quantum dot.

Research paper thumbnail of Transport properties of gated sub-micron mesas incorporating InAs self-assembled quantum dots that conduct near zero bias

Physica E: Low-dimensional Systems and Nanostructures, 2005

ABSTRACT We have fabricated multiple-gate vertical mesa transistors to investigate the Coulomb os... more ABSTRACT We have fabricated multiple-gate vertical mesa transistors to investigate the Coulomb oscillation and Coulomb diamond-like characteristics of a planar ensemble of self-assembled InAs quantum dots located in the central plane of a single 14nm Al0.2Ga0.8As tunnel barrier. The current–voltage characteristics are dominated by electron tunneling through the energy levels of just a few (∼10) dots. Since these dots are located at various distances from the mesa side walls, the dot energy levels up-shift at different rates when the gate-adjustable front of the depletion region spreads towards the center of the mesa. This results in Coulomb-diamond apexes with different gate voltage signatures.

Research paper thumbnail of Magneto-photoluminescence of stacked self-assembled InAs/GaAs quantum dots

Physica B: Condensed Matter, 2004

ABSTRACT We studied ten-fold stacked layers of self-assembled InAs/GaAs quantum dots by photolumi... more ABSTRACT We studied ten-fold stacked layers of self-assembled InAs/GaAs quantum dots by photoluminescence in pulsed magnetic fields. When the interlayer distance is reduced from 9.8 to , a doubling of the diamagnetic shift for a magnetic field perpendicular to the [001] direction reveals the onset of electron coupling between the dots in the stack. On reducing the interlayer distance to , a lower exciton effective mass is seen in addition to the coupling. For such a close stacking, the strain field in and around the dot is completely different from that of a single-layered structure. In particular, the strain inside the InAs dots in the stack is partially relaxed, causing the observed effect.

Research paper thumbnail of Strong Effect of Resonant Impurities on Landau-Level Quantization

Physical Review Letters - PHYS REV LETT, 2006

We investigate experimentally the effect of a random distribution of nitrogen (N) impurities on t... more We investigate experimentally the effect of a random distribution of nitrogen (N) impurities on the Landau-level spectrum of a GaAs quantum well. Our magnetotunneling study reveals complex and nonequally spaced Landau levels and a quenching of the Landau states at a well-defined bias and electron energy which is resonant with that of the N atoms. Analysis of the magnetic field dependence of the tunnel current into the Landau levels of the well also provides quantitative information about the nonresonant component of the N-related scattering potential.

Research paper thumbnail of Chaotic electron diffusion through stochastic webs enhances current flow in superlattices

Nature, 2004

IMBH via the process described above. So far, no bright X-ray source has been found in this cluster.

Research paper thumbnail of Fock-Darwin-Like Quantum Dot States Formed by Charged Mn Interstitial Ions

Physical Review Letters, 2008

We report a method of creating electrostatically induced quantum dots by thermal diffusion of int... more We report a method of creating electrostatically induced quantum dots by thermal diffusion of interstitial Mn ions out of a p-type (GaMn)As layer into the vicinity of a GaAs quantum well. This approach creates deep, approximately circular, and strongly confined dotlike potential minima in a large (200 microm) mesa diode structure without need for advanced lithography or electrostatic gating. Magnetotunneling spectroscopy of an individual dot reveals the symmetry of its electronic eigenfunctions and a rich energy level spectrum of Fock-Darwin-like states with an orbital angular momentum component |lz| from 0 to 11.

Research paper thumbnail of Strain relaxation in stacked InAs/GaAs quantum dots studied by Raman scattering

Applied Physics Letters, 2003

ABSTRACT We report a Raman scattering investigation of InAs vibrational modes in multiple layers ... more ABSTRACT We report a Raman scattering investigation of InAs vibrational modes in multiple layers of InAs self-assembled quantum dots in a GaAs matrix. The Raman peak associated with quantum-dot phonons shows a downward frequency shift as the interlayer spacing decreases. We attribute this frequency shift to the relaxation of the elastic strain in the stacked quantum-dot layers. From the phonon frequency shift, we estimate the magnitude of the strain in the quantum dot layers, which we relate to the energy of the photoluminescence emission of the dots. © 2003 American Institute of Physics.