Density-functional theory (DFT) for electrons at finite temperature is increasingly important in condensed matter and chemistry. The exact conditions that have proven crucial constraining constructing accurate approximations ground-state DFT are generalized to temperature, including the adiabatic connection formula. We discuss consequences functional construction.

The combined effect of finite potential barriers and the dielectric mismatch between dot matrix on excitonic properties semiconductor quantum dots has been studied. To avoid unphysical divergence in self-polarization energy which arises for simplest profusely adopted step-like model interface, we proposed a realistic (finite size) smooth profile interface. We have found that binding can either be higher than corresponding one to complete confinement by infinite or essentially zero wide range...

Oscillations in the thermopower of a quantum-point constriction absence and presence magnetic field are discussed.Received 25 March 1991DOI:https://doi.org/10.1103/PhysRevB.44.9096©1991 American Physical Society

The Becke-Johnson exchange potential [J. Chem. Phys. 124, 221101 (2006)] has been successfully used in electronic structure calculations within density-functional theory. However, its original form the may dramatically fail systems with non-Coulombic external potentials, or presence of magnetic electric fields. Here, we provide a system-independent correction to approximation by (i) enforcing gauge invariance and (ii) making it exact for any single-electron system. resulting is then better...

The transmission of electrons through a noninteracting tight-binding chain with an interacting side quantum dot (QD) is analyzed. When the Kondo effect develops at conductance presents wide minimum, reaching zero unitary limit. This result compared to opposite behavior found in embedded QD. Application magnetic field destroys and shows pairs dips separated by charging energy U. results are discussed terms Fano antiresonances explain qualitatively recent experimental results.

We study spinless fermions on a finite chain with nearest-neighbor repulsion and in the presence of Wannier-Stark linearly-varying electric field potential. In absence interaction, eigenstates are localized for system's sizes larger than localization length. present several analytical expressions length, which is proportional to inverse field. Using density matrix renormalization group numerical technique, we observe that ground state exhibits decrease occupation sites from `bulk', 1,...

The combined effect of shape and dielectric mismatch between dot matrix on several electronic properties semiconductor quantum dots have been studied. In particular, the spherical cubic that analyzed are integrated density states, polarization self-energy corrections to single-particle energies, doping with impurities, excitonic Coulomb blockade energies. It has found that, in spite highly nonhomogeneous polarized charge induced at boundaries dot, essentially independent for all range mismatch.

The problem of a donor impurity in confined geometry with dielectric mismatch at the boundaries has been studied. It is shown that limit dot size smaller than effective Bohr radius, admits an extremely simple perturbative solution for arbitrary locations. first-order energy corrections (``binding'' energy) are obtained analytically s- and p-like states, minimal numerical effort d,f,g,... states. Important charge-induced polarization effects found particular case silicon embedded amorphous...

Bounds on the exchange-correlation energy of many-electron systems are derived and tested. By using universal scaling properties electron-electron interaction, we obtain exponent bounds in three, two, one, quasione dimensions. From electron gas dilute regime, tightest estimate to date is given for numerical prefactor bound, which crucial practical applications. Numerical tests various low-dimensional line with obtained give evidence an interesting dimensional crossover between two one

We extend the Becke-Johnson approximation [J. Chem. Phys. 124, 221101 (2006)] of exchange potential to two dimensions. prove and demonstrate that a direct extension underlying formalism may lead divergent behavior potential. derive cure approach by enforcing gauge invariance correct asymptotic The procedure leads an which is shown, in various quasi-two-dimensional test systems, be very accurate comparison with exact potential, thus considerable improvement over commonly applied local-density...

The effective Hamiltonian for the linear $E\ensuremath{\bigotimes}e$ Jahn-Teller model describes coupling between two electronic states and vibrational modes in molecules or bulk crystal impurities. While Born-Oppenheimer approximation Berry curvature has a delta function singularity at conical intersection of potential energy surfaces, exact is smooth peaked function. Numerical calculations revealed that characteristic width peak $\ensuremath{\hbar}{\mathcal{K}}^{1/2}/g{\mathcal{M}}^{1/2}$,...

A broadly used strategy to go beyond the well-known local-density approximation of density functional theory relies on choice a so-called exchange-correlation (xc) enhancement factor ${F}_{\mathrm{xc}}$, defined as realistic xc energy over its local exchange-only counterpart. To date, this functional, has been constructed by following either semiempirical strategies or nonempirical schemes that impose fulfillment exact constraints. Here, we follow totally different route, which is based an...

The strong-confinement approach for the study of electronic properties semiconductor quantum dots has been generalized to case defined by a parabolic confining potential. ground and lowest-lying excited states donor impurity located anywhere in dot subject magnetic fields have analyzed with this approach. impurity-related binding energy depends strongly on position field strength. While most cases exhibits expected decrease distance between center coordinate, at small first increase their...

We study the integrability by means of Bethe ansatz a model which consists two 4f configurations total angular momentum ${J}_{0}$ and ${J}_{1}$ hybridized through promotion an electron ${j}_{e}$ to conduction band. For ${J}_{0}$=0 reduces degenerate Anderson model, while for ${J}_{0}$${J}_{1}$\ensuremath{\ne}0 it describes valence fluctuators between magnetic configurations. find that in addition case ${J}_{0}$${J}_{1}$=0, any ${j}_{e}$, is also exactly solvable ${j}_{e}$=(1/2)...

The position-dependent exact-exchange energy per particle ${\ensuremath{\epsilon}}_{x}(z)$ (defined as the interaction between a given electron at $z$ and its hole) metal surfaces is investigated, by using either jellium slabs or semi-infinite (SI) model. For slabs, we prove analytically numerically that in vacuum region far away from surface ${\ensuremath{\epsilon}}_{x}^{\text{Slab}}(z\ensuremath{\rightarrow}\ensuremath{\infty})\ensuremath{\rightarrow}\ensuremath{-}{e}^{2}/2z$, independent...

Using a simplified one-dimensional model of diatomic molecule, the associated interacting density and corresponding Kohn-Sham potential have been obtained analytically for all fractional molecule occupancies $N$ between 0 2. For homonuclear case, in dissociation limit, exact builds barrier at midpoint two atoms, whose strength increases linearly with $N$, $1 < N \leq 2$. In heteronuclear disociating KS besides also exhibits plateau around atom higher ionization potential, size (but not its...

We study the current through a quantum wire side-coupled to dot, and compare it with case of an embedded dot. The system is modeled after Anderson Hamiltonian for linear chain, one atom either coupled (side dot) or substituted by (embedded magnetic impurity. For realistic (small) hopping dot rest system, exact relationship between both conductivities holds. calculate temperature dependence moderate values Coulomb repulsion U using interpolative perturbative scheme. sufficiently large greater...

The single-particle electronic spectra of semiconductor self-assembled quantum rings are theoretically analyzed. We studied two different models for the lateral confining potential: displaced parabola (Hill) and centrifugal-like core (Volcano). corresponding energy levels systematically analyzed as a function both ring radius, external magnetic fields perpendicular to plane. one-electron ground state Hill potential presents an absolute minimum when radius. Numerically exact approximate...

Using a generalized Hubbard model, we study the neutral-ionic transition and stability of dimerized phases in mixed-stack compounds by means real-space renormalization-group technique. The model includes hybridization between relevant orbitals donor acceptor molecules, intramolecular Coulomb repulsion which is taken to be infinite avoid double ionization, nearest-neighbor electron-electron interactions. We present phase diagram, occupation (acceptor) minimum electron-hole excitation energies...

The behavior of the surface barrier that forms at metal-vacuum interface is important for several fields science. Within Density Functional Theory framework, this has two non-trivial components: exchange and correlation. Exact results are provided component, a jellium interface, in slab geometry. Kohn-Sham exact-exchange potential $V_{x}(z)$ been generated by using Optimized Effective Potential method, through an accurate numerical solution, imposing correct boundary condition. It proved...

Density functional theory is generalized to incorporate electron-phonon coupling. A Kohn-Sham equation yielding the electronic density ${n}_{U}(\mathbf{r})$, a conditional probability depending parametrically on phonon normal mode amplitudes $U={{U}_{\mathbf{q}\ensuremath{\lambda}}}$, coupled nuclear Schr\"odinger of exact factorization method. The modes are defined from harmonic expansion equation. nonzero Berry curvature configuration space affects modes, showing that potential energy...

The size dependence of the one-particle band gap and Coulomb exchange excitonic corrections spherical quantum dots are calculated using effective-mass approximation with finite confining potentials. Full analytical expressions found for three magnitudes, it is shown that in good qualitative quantitative agreement available state-of-the-art calculations (for Si, GaAs, CdSe) experiments InP).

The properties of excitons in inhomogeneous quantum dots have been theoretically studied the strong confinement regime; these an internal structure, with inner core that behaves as a repulsive potential for electrons and holes. model includes rigorous (macroscopic) treatment dielectric mismatch at dot boundaries. Analytical (numerical) results are obtained ground- (excited-) state exciton. It is found all cases exciton binding energy decreases by increasing size region; on other hand,...

Quantum rings can be characterized by a specific radius and ring width. For this rich class of physical systems, an accurate approximation for the exchange-hole potential thus exchange energy is derived from first principles. Excellent agreement with exact-exchange results obtained regardless parameters, total spin, current, or external magnetic field. The description applied as density functional outperforming commonly used local spin-density approximation, which here explicitly shown to...

The capability of density-functional theory to deal with the ground state strongly correlated low-dimensional systems, such as semiconductor quantum dots, depends on accuracy functionals developed for exchange and correlation energies. Here we extend a successful approximation energy three-dimensional inhomogeneous electron gas, originally introduced by Becke [J. Chem. Phys. 88, 1053 (1988)], two-dimensional case. approach is based nonempirical modeling correlation-hole functions satisfying...