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

Abstract

A theory of hot electron cooling power due to polar optical phonons P is developed in 3D Dirac semimetal (3DDS) CdAs taking account of hot phonon effect. Hot phonon distribution N and P are investigated as a function of electron temperature T , electron density n, and phonon relaxation time [Formula: see text]. It is found that P increases rapidly (slowly) with T at lower (higher) temperature regime. Whereas, P is weakly decreasing with increasing n. The results are compared with those for three-dimensional electron gas (3DEG) in CdAs semiconductor. Hot phonon effect is found to reduce P considerably and it is stronger in 3DDS CdAs than in CdAs semiconductor. P is also compared with the hot electron cooling power due to acoustic phonons P. We find that a crossover takes place from P dominated cooling at low T to P dominated cooling at higher T. The temperature at which this crossover occurs shifts towards higher values with the increase of n . Also, hot electron energy relaxation time [Formula: see text] is discussed. It is suggested that [Formula: see text] can be tuned to achieve faster or slower energy loss for suitable applications of CdAs.

Large power dissipation of hot Dirac fermions in twisted bilayer graphene

“…2 (T e 2 − T 2 )/(6E F P )], where p is the exponent of energy in density of states and E F is the Fermi energy [20,36]. In BG regime, since P ∼ T e 4 and n s −1/2 , we find τ e ∼ T e −2…”

Phonon-limited mobility of Dirac fermions in three-dimensional Dirac semimetal Cd3As2

“…In the study of momentum relaxation time [30], scattering due to acoustic phonon coupling is briefly addressed. The P calculations show the dominance of the scattering by optical phonons for T > ~25 K [35]. However, there are no studies so far of the electron momentum relaxation and mobility due to scattering by optical phonons in 3DDS Cd 3 As 2 , which is expected to govern the transport at higher temperatures.…”

Drift velocity saturation and large current density in intrinsic three-dimensional Dirac semimetal cadmium arsenide

“…We consider the electron-optical phonon interaction via Fröhlich interaction and the corresponding matrix element is given by │C(q)│ 2 = (C0/q 2 ) (1+cosθ)/2, where C0 = (2πe 2 ħω0ε′)/V, ħωq = ħω0 is the optical phonon energy, ε′ = (ε∞ -1 -εs -1 ), and ε∞ (εs) is the highfrequency (static) dielectric constant. In high electric field, the optical phonon distribution will deviate from its thermal equilibrium value Nq (T) and it is given by the hot phonon distribution function Nqhp [25].…”

“…and Equ = (2Ek+ħω0)/2. The equation (8) is obtained from our work [25] by combining Eqs. (16) and (6) It should be noted that the method adopted here to obtain vd as a function of E is analytical, unlike other numerical methods [29,32,36,37].…”