High phonon-limited mobility of BAs under pressure

Abstract

Recent experiment reports that high thermal conductivity of ~1000 W/mK is observed in cubic boron arsenide crystal (BAs). In order to expand the scope of future applications, we use first-principles calculations to investigate the phonon-limited electronic transport in BAs family and modulation effect of pressure. In the case of electron doping, BAs, AlAs and AlSb exhibit the coupling between high frequency optical phonons and electron as well as the low frequency acoustical phonons in BSb. And BAs has the weakest electron-phonon coupling thus has a high N-type carrier mobility of 1740 cm^2/Vs. After the introduction of pressure, phonon spectra has more obvious change than the electronic structure. The phonon hardening under the pressure gives rise to the weakening of electron-phonon coupling. It is obtained that the pressure of 50 GPa can improve the mobility of BAs up to 4300 cm^2/Vs, which is much high and great significance to the current semiconductor industry.