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Papers by Cheche Tiberius
A detailed theoretical description of the "resonance treatment" based on Bloch equation... more A detailed theoretical description of the "resonance treatment" based on Bloch equations is presented for a dissipative two-state system, in the limit of weak coupling between a mi-croscopic subsystem and its environment, using the framework of the "spin-boson" model. For an Ohmic spectral density function, the dynamics of the transition probability for an overdamped regime is applied in the case of the primary electron transfer reaction in a bacterial photosynthetic reaction center.
A formal expression of the one-exciton absorption coefficient is derived by a nonadiabatic treatm... more A formal expression of the one-exciton absorption coefficient is derived by a nonadiabatic treatment, which takes into account the exciton-phonon interaction. The approach is built in the Fermi Golden Rule and dipole approximation framework. It recovers the well-known results of the adiabatic approximation.
The Euler’s laws and Lagrange’s equations are shortly presented in a directly applicable form to ... more The Euler’s laws and Lagrange’s equations are shortly presented in a directly applicable form to a problem of classical mechanics. The proposed problem offers a didactical tool to observe how the equations of the plane motion of a rigid body could be applied and understood from the perspective of Newton and Lagrange mechanics. For simulation of the proposed motion some concrete calculus are presented
Journal of the Chinese Chemical Society, 2000
ABSTRACT Starting from the von Neuman equation of quantum theoretical dynamics, by using the proj... more ABSTRACT Starting from the von Neuman equation of quantum theoretical dynamics, by using the projection operator technique, we write the generalised master equation (GME) of the reduced statistical operator. By using this technique we find a series expansion of the memory kernel which allows, in principle, a treatment of the higher orders of approximation. By keeping only the first term of this expansion, which corresponds to the second order of the perturbation treatment, GME is applied, in the Markov approximation, to the spin boson Hamiltonian to describe the dynamics of the relevant pseudo-spin subsystem. In the secular and rotating wave approximations this dynamics is found to be described by the Bloch equations.
Chemical Physics Letters, 2014
The lattice mismatch strain field of core/multishell structures with spherical symmetry is modele... more The lattice mismatch strain field of core/multishell structures with spherical symmetry is modeled by a linear continuum elasticity approach. The effect of the strain on the energy structure and linear optical absorption in large core/shell/shell spherical semiconductor quantum dots is analyzed. Localization of the photoexcited carriers induced by coating is found to play an important role in explaining the optical stability of large CdSe/CdS/ZnS and ZnTe/ZnSe/ZnS quantum dots.
Superlattices and Microstructures, 2013
A one-band model within the effective mass approximation is adopted to characterize the energy st... more A one-band model within the effective mass approximation is adopted to characterize the energy structure and oscillator strength of type-II semiconductor spherical coreshell quantum dots. The heteroepitaxial strain of the core-shell heterostructure is modeled by the elastic continuum approach. The model is applied to ZnTe/ZnSe coreshell, a wide band gap type-II heterostructure. The simulated absorption spectra are in fair agreement with available experimental results. I.
Physical Review B, 2006
The intrinsic spin Hall conductivity is calculated for a two-dimensional electronic gas (2DEG) in... more The intrinsic spin Hall conductivity is calculated for a two-dimensional electronic gas (2DEG) in presence of strain, Rashba coupling, and an external inplane applied magnetic field. The conduction electrons of [001] oriented quantum well (QW) are used to model the 2DEG. For a stress applied in the growth direction of QW the intrinsic dc spin Hall conductivity is not dependent on the strain and the inplan applied magnetic field, and it has the universal value, π 8 / e .
Physica B: Condensed Matter, 2011
ABSTRACT The exciton–longitudinal optical phonon interaction is theoretically investigated for th... more ABSTRACT The exciton–longitudinal optical phonon interaction is theoretically investigated for the case of polar semiconductor cylindrical quantum dots embedded in semiconductor matrix. The theory is developed within the dielectric continuum model considering the Fröhlich interaction between electrons and confined bulk longitudinal optical phonons for a configurational interaction model of quantum dot. Representative longitudinal optical phonon mode for the exciton–phonon interaction is predicted for cylindrical InAs/GaAs quantum dots.
Journal of Applied Physics, 2008
The problems of strain and piezoelectric effect are solved for a buried semiconductor quantum dot... more The problems of strain and piezoelectric effect are solved for a buried semiconductor quantum dot (QD) of conical shape with wetting layer, within continuum elastic model. Analytical results are obtained for the isotropic case of the elasticity. For the isotropic dielectric constant case, we provide an analytical expression of the piezoelectric potential. An extension of Eshleby's continuum elasticity theory of inclusions [J. D. Eshelby, Proc. R. Soc. London, Ser. A, 376 (1957)] to QDs with wetting layers is adopted. The results for self-assembled InAs/GaAs QDs are compared with numerical results obtained with an atomistic model based on the valence force field method. We find good agreement between the results obtained with the two methods.
Chemical Physics Letters, 2005
ABSTRACT The presence of accompanying resonances to the longitudinal optical phonon satellites in... more ABSTRACT The presence of accompanying resonances to the longitudinal optical phonon satellites in the optical spectra of semiconductor quantum dots is confirmed theoretically by a non-adiabatic approach of the optical absorption. The theory is applied to simulate features of the optical spectra of small spherical GaAs/AlAs quantum dots. The intensity and the spectral position of the accompanying resonances are influenced by both optically active and dark levels and increase to measurable values with temperature.
Chemical Physics, 2012
Existence of representative longitudinal optical (LO) phonon modes is theoretically discussed for... more Existence of representative longitudinal optical (LO) phonon modes is theoretically discussed for the case of polar semiconductor cylindrical quantum dots embedded in a semiconductor matrix. The approach is developed within the dielectric continuum model considering the Fröhlich interaction between electrons and the confined LO phonons. The theory is applied to cylindrical GaAs/AlAs quantum dots within an adiabatic treatment.
Chemical Physics, 2005
Optical absorption of quantum dots is investigated using the adiabatic approach, in which a Frö h... more Optical absorption of quantum dots is investigated using the adiabatic approach, in which a Frö hlich-type interaction between electron-hole pair and longitudinal optical phonons has been assumed. The role of the finite barrier potentials in predicting the magnitude of the Huang-Rhys factors is considered. For the small GaAs/AlAs quantum dots, the Huang-Rhys factors are found to be larger than those in the bulk phase by one to two orders of magnitude. The absorption and photoluminescence spectra of such nanostructures are analyzed.
Chemical Physics, 1999
The dynamics of a macroscopic dissipative two-state system are approached in the weak coupling li... more The dynamics of a macroscopic dissipative two-state system are approached in the weak coupling limit by using a resonance treatment developed within the framework of the spin-boson model. The longitudinal and transversal relaxation times are obtained by applying the quantum relaxation theory. The model is tested to find the rate constants for non-adiabatic electron transfer reactions in photosynthetic reaction centers in the case of weak coupling between the microscopic two-state subsystem and its environment.
Chemical Physics, 1998
ABSTRACT A `resonance treatment' is applied to a dissipative two-state system, in the lim... more ABSTRACT A `resonance treatment' is applied to a dissipative two-state system, in the limit of weak coupling between its electronic states and its environment (heat bath), using the frame of the `spin–boson' model. We find the dynamics of the system as function of temperature and its energy characteristics. The treatment is applied to electron transfer reactions in solutions, for solvents with short longitudinal relaxation times.
Chemical Physics, 2001
In the second-order approximation, the Markovian generalised master equation is applied to the sp... more In the second-order approximation, the Markovian generalised master equation is applied to the spin-boson Hamiltonian to find the dynamics of a dissipative two-state subsystem (TSS). The results are compared with those obtained by the path-integral formalism and considered to evaluate the possibility of apparition of electronic coherence for the electron transfer reaction in certain photosynthetic reaction centers.
Applied Physics Letters, 2006
The intrinsic spin Hall conductivity is obtained for a two-dimensional electronic gas (2DEG) in p... more The intrinsic spin Hall conductivity is obtained for a two-dimensional electronic gas (2DEG) in presence of strain, Rashba coupling and an external in-plane applied magnetic field. The conduction electrons of [001] oriented quantum well (QW) are used to model the 2DEG. The spin current value is dependent on the stress applied in direction [111].
Fingerprints in the Optical and Transport Properties of Quantum Dots, 2012
A detailed theoretical description of the "resonance treatment" based on Bloch equation... more A detailed theoretical description of the "resonance treatment" based on Bloch equations is presented for a dissipative two-state system, in the limit of weak coupling between a mi-croscopic subsystem and its environment, using the framework of the "spin-boson" model. For an Ohmic spectral density function, the dynamics of the transition probability for an overdamped regime is applied in the case of the primary electron transfer reaction in a bacterial photosynthetic reaction center.
A formal expression of the one-exciton absorption coefficient is derived by a nonadiabatic treatm... more A formal expression of the one-exciton absorption coefficient is derived by a nonadiabatic treatment, which takes into account the exciton-phonon interaction. The approach is built in the Fermi Golden Rule and dipole approximation framework. It recovers the well-known results of the adiabatic approximation.
The Euler’s laws and Lagrange’s equations are shortly presented in a directly applicable form to ... more The Euler’s laws and Lagrange’s equations are shortly presented in a directly applicable form to a problem of classical mechanics. The proposed problem offers a didactical tool to observe how the equations of the plane motion of a rigid body could be applied and understood from the perspective of Newton and Lagrange mechanics. For simulation of the proposed motion some concrete calculus are presented
Journal of the Chinese Chemical Society, 2000
ABSTRACT Starting from the von Neuman equation of quantum theoretical dynamics, by using the proj... more ABSTRACT Starting from the von Neuman equation of quantum theoretical dynamics, by using the projection operator technique, we write the generalised master equation (GME) of the reduced statistical operator. By using this technique we find a series expansion of the memory kernel which allows, in principle, a treatment of the higher orders of approximation. By keeping only the first term of this expansion, which corresponds to the second order of the perturbation treatment, GME is applied, in the Markov approximation, to the spin boson Hamiltonian to describe the dynamics of the relevant pseudo-spin subsystem. In the secular and rotating wave approximations this dynamics is found to be described by the Bloch equations.
Chemical Physics Letters, 2014
The lattice mismatch strain field of core/multishell structures with spherical symmetry is modele... more The lattice mismatch strain field of core/multishell structures with spherical symmetry is modeled by a linear continuum elasticity approach. The effect of the strain on the energy structure and linear optical absorption in large core/shell/shell spherical semiconductor quantum dots is analyzed. Localization of the photoexcited carriers induced by coating is found to play an important role in explaining the optical stability of large CdSe/CdS/ZnS and ZnTe/ZnSe/ZnS quantum dots.
Superlattices and Microstructures, 2013
A one-band model within the effective mass approximation is adopted to characterize the energy st... more A one-band model within the effective mass approximation is adopted to characterize the energy structure and oscillator strength of type-II semiconductor spherical coreshell quantum dots. The heteroepitaxial strain of the core-shell heterostructure is modeled by the elastic continuum approach. The model is applied to ZnTe/ZnSe coreshell, a wide band gap type-II heterostructure. The simulated absorption spectra are in fair agreement with available experimental results. I.
Physical Review B, 2006
The intrinsic spin Hall conductivity is calculated for a two-dimensional electronic gas (2DEG) in... more The intrinsic spin Hall conductivity is calculated for a two-dimensional electronic gas (2DEG) in presence of strain, Rashba coupling, and an external inplane applied magnetic field. The conduction electrons of [001] oriented quantum well (QW) are used to model the 2DEG. For a stress applied in the growth direction of QW the intrinsic dc spin Hall conductivity is not dependent on the strain and the inplan applied magnetic field, and it has the universal value, π 8 / e .
Physica B: Condensed Matter, 2011
ABSTRACT The exciton–longitudinal optical phonon interaction is theoretically investigated for th... more ABSTRACT The exciton–longitudinal optical phonon interaction is theoretically investigated for the case of polar semiconductor cylindrical quantum dots embedded in semiconductor matrix. The theory is developed within the dielectric continuum model considering the Fröhlich interaction between electrons and confined bulk longitudinal optical phonons for a configurational interaction model of quantum dot. Representative longitudinal optical phonon mode for the exciton–phonon interaction is predicted for cylindrical InAs/GaAs quantum dots.
Journal of Applied Physics, 2008
The problems of strain and piezoelectric effect are solved for a buried semiconductor quantum dot... more The problems of strain and piezoelectric effect are solved for a buried semiconductor quantum dot (QD) of conical shape with wetting layer, within continuum elastic model. Analytical results are obtained for the isotropic case of the elasticity. For the isotropic dielectric constant case, we provide an analytical expression of the piezoelectric potential. An extension of Eshleby's continuum elasticity theory of inclusions [J. D. Eshelby, Proc. R. Soc. London, Ser. A, 376 (1957)] to QDs with wetting layers is adopted. The results for self-assembled InAs/GaAs QDs are compared with numerical results obtained with an atomistic model based on the valence force field method. We find good agreement between the results obtained with the two methods.
Chemical Physics Letters, 2005
ABSTRACT The presence of accompanying resonances to the longitudinal optical phonon satellites in... more ABSTRACT The presence of accompanying resonances to the longitudinal optical phonon satellites in the optical spectra of semiconductor quantum dots is confirmed theoretically by a non-adiabatic approach of the optical absorption. The theory is applied to simulate features of the optical spectra of small spherical GaAs/AlAs quantum dots. The intensity and the spectral position of the accompanying resonances are influenced by both optically active and dark levels and increase to measurable values with temperature.
Chemical Physics, 2012
Existence of representative longitudinal optical (LO) phonon modes is theoretically discussed for... more Existence of representative longitudinal optical (LO) phonon modes is theoretically discussed for the case of polar semiconductor cylindrical quantum dots embedded in a semiconductor matrix. The approach is developed within the dielectric continuum model considering the Fröhlich interaction between electrons and the confined LO phonons. The theory is applied to cylindrical GaAs/AlAs quantum dots within an adiabatic treatment.
Chemical Physics, 2005
Optical absorption of quantum dots is investigated using the adiabatic approach, in which a Frö h... more Optical absorption of quantum dots is investigated using the adiabatic approach, in which a Frö hlich-type interaction between electron-hole pair and longitudinal optical phonons has been assumed. The role of the finite barrier potentials in predicting the magnitude of the Huang-Rhys factors is considered. For the small GaAs/AlAs quantum dots, the Huang-Rhys factors are found to be larger than those in the bulk phase by one to two orders of magnitude. The absorption and photoluminescence spectra of such nanostructures are analyzed.
Chemical Physics, 1999
The dynamics of a macroscopic dissipative two-state system are approached in the weak coupling li... more The dynamics of a macroscopic dissipative two-state system are approached in the weak coupling limit by using a resonance treatment developed within the framework of the spin-boson model. The longitudinal and transversal relaxation times are obtained by applying the quantum relaxation theory. The model is tested to find the rate constants for non-adiabatic electron transfer reactions in photosynthetic reaction centers in the case of weak coupling between the microscopic two-state subsystem and its environment.
Chemical Physics, 1998
ABSTRACT A `resonance treatment' is applied to a dissipative two-state system, in the lim... more ABSTRACT A `resonance treatment' is applied to a dissipative two-state system, in the limit of weak coupling between its electronic states and its environment (heat bath), using the frame of the `spin–boson' model. We find the dynamics of the system as function of temperature and its energy characteristics. The treatment is applied to electron transfer reactions in solutions, for solvents with short longitudinal relaxation times.
Chemical Physics, 2001
In the second-order approximation, the Markovian generalised master equation is applied to the sp... more In the second-order approximation, the Markovian generalised master equation is applied to the spin-boson Hamiltonian to find the dynamics of a dissipative two-state subsystem (TSS). The results are compared with those obtained by the path-integral formalism and considered to evaluate the possibility of apparition of electronic coherence for the electron transfer reaction in certain photosynthetic reaction centers.
Applied Physics Letters, 2006
The intrinsic spin Hall conductivity is obtained for a two-dimensional electronic gas (2DEG) in p... more The intrinsic spin Hall conductivity is obtained for a two-dimensional electronic gas (2DEG) in presence of strain, Rashba coupling and an external in-plane applied magnetic field. The conduction electrons of [001] oriented quantum well (QW) are used to model the 2DEG. The spin current value is dependent on the stress applied in direction [111].
Fingerprints in the Optical and Transport Properties of Quantum Dots, 2012