Electron cooling in three-dimensional Dirac fermion systems at low temperature: Effect of screening

Abstract

Hot electron cooling rate P, due to acoustic phonons, is investigated in three‐dimensional Dirac fermion systems at low temperature taking account of the screening of electron–acoustic phonon interaction. P is studied as a function of electron temperature Te and electron concentration ne. Screening is found to suppress P very significantly for about Te < 0.5 K and its effect reduces considerably for about Te > 1 K in Cd3As2. In Bloch–Grüneisen (BG) regime, for screened (unscreened) case the Te dependence is P ∼ Te9(Te5) and the ne dependence gives P ∼ ne–5/3 (ne–1/3). The Te dependence is characteristic of 3D phonons and ne dependence is characteristics of 3D Dirac fermions. The plot of P /Te4 vs. Te shows a maximum at temperature Tem which shifts to higher values for larger ne. Interestingly, the maximum is nearly same for different ne and Tem/ne1/3 being nearly constant. More importantly, we propose, the ne dependent measurements of P would provide a clearer signature to identify 3D Dirac semimetal phase. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)

Hot electron cooling in Dirac semimetal Cd3As2 due to polar optical phonons

“…In the Bloch-Grüneisen (BG) regime, T e ≪ T BG =(2 v s k F /k B ), where k F is the Fermi wave vector, the P ac dependence on T e and n e are shown to be given by the power laws P ac ∼ T α e and n −δ e where α=9(5) and δ=5/3(1/3) with(without) screening of electron-acoustic phonon interaction 38 . In relatively higher T e (> T BG ) regime, disorder assisted P ac calculations show drastic increase of cooling power due to enhanced energy transfer between electrons and acoustic phonons 37 .…”

Similar ultrafast dynamics of several dissimilar Dirac and Weyl semimetals

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Resistivity of Weyl semimetals NbP and TaP under pressure

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