Nonadiabatic wavepacket dynamics: k-space formulation
arXiv:0810.2057 · doi:10.1103/PhysRevB.79.045127
Abstract
The time evolution of wavepackets in crystals in the presence of a homogeneous electric field is formulated in k-space in a numerically tractable form. The dynamics is governed by separate equations for the motion of the waveform in k-space and for the evolution of the underlying Bloch-like states. A one-dimensional tight-binding model is studied numerically, and both Bloch oscillations and Zener tunneling are observed. The long-lived Bloch oscillations of the wavepacket center under weak fields are accompanied by oscillations in its spatial spread. These are analyzed in terms of a k-space expression for the spread having contributions from both the quantum metric and the Berry connection of the Bloch states. We find that when sizeable spread oscillations do occur, they are mostly due to the latter term.
References in corpus (7)
- Maximally-localized generalized Wannier functions for composite energy bands
- Bloch oscillations and mean-field effects of Bose-Einstein condensates in 1-D optical lattices
- A First-Principles Approach to Insulators in Finite Electric Fields
- Polarization and localization in insulators: generating function approach
- Experimental properties of Bose-Einstein condensates in 1D optical lattices: Bloch oscillations, Landau-Zener tunneling and mean-field effects
- Dynamics of Berry-phase polarization in time-dependent electric fields
- Coherent wave-packet evolution in coupled bands