Time-dependent current-density-functional theory for the metallic response of solids

Current-density functional theory of the response of solids

The response of an extended periodic system to a homogeneous field ~of wave-vector q50) cannot be obtained from a q50 time-dependent density functional theory ~TDDFT! calculation, because the RungeGross theorem does not apply. Time-dependent current–density functional theory is needed and demonstrates that one key ingredient missing from TDDFT is the macroscopic current. In the low-frequency li...

Stochastic time-dependent current-density-functional theory.

A time-dependent current-density-functional theory for many-particle systems in interaction with arbitrary external baths is developed. We prove that, given the initial quantum state |Psi0> and the particle-bath interaction operator, two external vector potentials A(r,t) and A'(r,t) that produce the same ensemble-averaged current density, j(r,t), must necessarily coincide up to a gauge transfor...

Real-time linear response for time-dependent density-functional theory.

We present a linear-response approach for time-dependent density-functional theories using time-adiabatic functionals. The resulting theory can be performed both in the time and in the frequency domain. The derivation considers an impulsive perturbation after which the Kohn-Sham orbitals develop in time autonomously. The equation describing the evolution is not strictly linear in the wave funct...

Time - dependent current - density - functional theory for molecules

Electron-phonon coupling in metallic solids from density functional theory

We present a study of electron-phonon coupling and superconductivity in metallic systems, based on first-principles electronic structure and linear response calculations. Our results are based on the density functional theory and are derived by using the full-potential linear muffin-tin orbitals method. In particular, calculations for phonon spectra, Eliashberg spectral function, and electron-p...