The kinetic theory of ultra-subsonic fermion systems and applications to flat band magic angle twisted bilayer graphene

Fuente: arXiv
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Autori principali: Davis, Seth M., Sarma, Sankar Das
Natura: Preprint
Pubblicazione: 2023
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author Davis, Seth M.
Sarma, Sankar Das
author_facet Davis, Seth M.
Sarma, Sankar Das
contents The only kinematically-allowed phonon-scattering events for bands of subsonic fermions ($v_F < v_p$) are interband transitions, leading to different low-$T$ transport physics than in the typical supersonic case. We apply a kinetic theory of phonon-limited transport to a generic two-band system of subsonic fermions, deriving formulae for relaxation times and resistivity that are accurate in the limit of close bands and small $v_F/v_p$. We predict regimes of $ρ\propto T$, $ρ\propto T^2$, and perfect conductivity. Our theory predicts linear-in-$T$ resistivity down to a crossover temperature that is suppressed from its supersonic analogue by a factor of $v_F/v_p$, offering a new explanation for low-$T$ "strange metal" behavior observed in flat band systems.
format Preprint
id arxiv_https___arxiv_org_abs_2305_09120
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle The kinetic theory of ultra-subsonic fermion systems and applications to flat band magic angle twisted bilayer graphene
Davis, Seth M.
Sarma, Sankar Das
Mesoscale and Nanoscale Physics
Materials Science
The only kinematically-allowed phonon-scattering events for bands of subsonic fermions ($v_F < v_p$) are interband transitions, leading to different low-$T$ transport physics than in the typical supersonic case. We apply a kinetic theory of phonon-limited transport to a generic two-band system of subsonic fermions, deriving formulae for relaxation times and resistivity that are accurate in the limit of close bands and small $v_F/v_p$. We predict regimes of $ρ\propto T$, $ρ\propto T^2$, and perfect conductivity. Our theory predicts linear-in-$T$ resistivity down to a crossover temperature that is suppressed from its supersonic analogue by a factor of $v_F/v_p$, offering a new explanation for low-$T$ "strange metal" behavior observed in flat band systems.
title The kinetic theory of ultra-subsonic fermion systems and applications to flat band magic angle twisted bilayer graphene
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2305.09120