Dresden 2006 – scientific programme
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HL: Halbleiterphysik
HL 50: Poster II
HL 50.61: Poster
Thursday, March 30, 2006, 16:30–19:00, P3
Time-dependent density functional theory in the non-adiabatic regime — •Günther Schwarz, Ilya V. Tokatly, and Oleg Pankratov — Chair of theoretical solid state physics - University of Erlangen-Nuremberg, Germany
The time-dependent density functional theory (TD-DFT) has proven to be an important scheme for the computation of dynamics of quantum mechanical systems. However, most of the work has been performed within the adiabatic local density approximation (ALDA) where the exchange-correlation potential vxc is treated as a local function of electron density. Recent work [1,2] has shown that a non-adiabatic TD-DFT can be formulated most naturally in the co-moving Lagrangian reference frame. Within this approach the time evolution of vxc is defined by a Cauchy deformation tensor as the basic variable rather than by the electron density or current. A differential equation for this tensor has to be solved in addition to the time-dependent Kohn-Sham equations. This imposes only modest computational effort over an adiabatic calculation.
We performed first tests of the dynamics of an electron gas in a single and double quantum well to demonstrate the similarities and differences of this generalized hydrodynamics approach as compared to adiabatic calculations. We aim to uncover the importance of non-adiabatic effects and thus to verify the applicability range of ALDA.
[1] I. V. Tokatly and O. Pankratov, Phys. Rev. B 37, 201103(R) (2003).
[2] I. V. Tokatly, Phys. Rev. B 71, 165105 (2005).