ELFT HÍRADÓ

[Janos Asboth <asboth AT phy.bme.hu>]

Meghívó

BME Elméleti Fizika Szeminárium,

május 7. péntek 10h15,
online a Microsoft Teams-ben
<https://teams.microsoft.com/l/meetup-join/19%3a35c712c192104aa998ed6bab3f0cbc07%40thread.tacv2/1620290825777?context=%7b%22Tid%22%3a%226a3548ab-7570-4271-91a8-58da00697029%22%2c%22Oid%22%3a%22c7eaf7d2-684b-4597-b217-6a9121400219%22%7d>
Okvátovity Zoltán (BME Elm. Fiz. tanszék):
Time dependent electric transport in nodal loop semimetals

Close to the Fermi energy, nodal loop semimetals have a torus-shaped,
strongly anisotropic Fermi surface which affects their transport
properties. Here we investigate the non-equilibrium dynamics of nodal loop
semimetals by going beyond linear response and determine the time evolution
of the current after switching on a homogeneous electric field. The current
grows monotonically with time for electric fields perpendicular to the
nodal loop plane, however, it exhibits non-monotonical behavior for field
orientations aligned within the plane. After an initial non-universal
growth ~*Et*, the current first reaches a plateau *~E*. Then, for
perpendicular directions, it increases while for in-plane directions it
decreases with time to another plateau, still ~*E*. These features arise
from interband processes. For long times or strong electric fields, the
current grows as *~E^(3/2)t* or *~E^3t^2* for perpendicular or parallel
electric fields, respectively. This non-linear response represents an
intraband effect where the large number of excited quasiparticles responds
to the electric field. Our analytical results are benchmarked by the
numerical evaluation of the current from continuum and tight-binding models
of nodal loop semimetals.

Manuscript: Z. Okvatovity, L. Oroszlany, B. Dora, arXiv:2104.07632)

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Asbóth János
szemináriumi koordinátor