2019/02/03 by Troy Stedman, Stedman, Troy, Carsten Timm +3
Physics and Astronomy · Engineering · #Quantum and electron transport phenomena #Terahertz technology and applications #Advanced Chemical Physics Studies
paper · pdf · doi:10.48550/arxiv.1902.00982
The equations of motion for the position and gauge invariant crystal momentum\nare considered for multiband wave packets of Bloch electrons. For a localized\npacket in a subset of bands well-separated from the rest of the band structure\nof the crystal, one can construct an effective electromagnetic Hamiltonian with\nrespect to the center of the packet. We show that the equations of motion can\nbe obtained via a projection operator procedure, which is derived from the\nadiabatic approximation within perturbation theory. These relations explicitly\ncontain information from each band captured in the expansion coefficients and\nenergy band structure of the Bloch states as well as non-Abelian features\noriginating from interband Berry phase properties. This general and transparent\nHamiltonian-based approach is applied to a wave packet spread over a single\nband, a set of degenerate bands, and two linear crossing bands. The generalized\nequations of motion hold promise for novel effects in transport currents and\nHall effect phenomena.\n