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Condensed Matter Seminar – Matthew Lapa (Univ. Chicago)

Date February 25, 2019 @ 4:00 pm - 5:00 pm

Semi-classical wave packet dynamics in non-uniform electric fields

Abstract: We study the semi-classical theory of wave packet dynamics in crystalline solids extended to include the effects of a non-uniform electric field. In particular, we derive a correction to the semi-classical equations of motion (EOMs) for the dynamics of the wave packet center that depends on the gradient of the electric field and on the quantum metric (also called the Fubini-Study, Bures, or Bloch metric) on the Brillouin zone. We show that the physical origin of this term is a contribution to the total energy of the wave packet that depends on its electric quadrupole moment and on the electric field gradient. Finally, we explore the physical consequences of this correction to the semi-classical EOMs. We show that in a metal with broken time-reversal and inversion symmetry, an electric field gradient can generate a longitudinal current which is proportional to the electric field gradient and to the quantum metric at the Fermi surface. Our results imply that non-uniform electric fields can be used to probe the quantum geometry of the electronic bands in metals and also suggest several directions for future research in this area.

Details

Date:
February 25, 2019
Time:
4:00 pm - 5:00 pm
Event Categories:
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Venue

2205 NPB