Wijewardane H O, Ullrich C A
Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, USA.
Phys Rev Lett. 2005 Aug 19;95(8):086401. doi: 10.1103/PhysRevLett.95.086401. Epub 2005 Aug 15.
In time-dependent density-functional theory, exchange and correlation (xc) beyond the adiabatic approximation can be described by viscoelastic stresses in the electron liquid. In the time domain, the resulting velocity-dependent xc vector potential has a memory containing short- and long-range components, leading to decoherence and energy relaxation. We solve the associated time-dependent Kohn-Sham equations, including the dependence on densities and currents at previous times, for the case of charge-density oscillations in a quantum well. We illustrate xc memory effects, clarify the dissipation mechanism, and extract intersubband relaxation rates for weak and strong excitations.
在含时密度泛函理论中，超出绝热近似的交换关联（xc）可由电子液体中的粘弹性应力来描述。在时域中，由此产生的与速度相关的xc矢量势具有包含短程和长程分量的记忆，导致退相干和能量弛豫。对于量子阱中电荷密度振荡的情况，我们求解了相关的含时Kohn-Sham方程，其中包括对先前时刻密度和电流的依赖。我们展示了xc记忆效应，阐明了耗散机制，并提取了弱激发和强激发下的子带间弛豫率。
