Kristen Kaasbjerg, Antti-Pekka Jauho, Kristian S. Thygesen
We theoretically study the acoustic phonon-limited mobility in two-dimensional n-doped MoS2 for temperatures T < 100 K and high carrier densities using the Boltzmann equation and first-principles calculations of the electron-phonon interaction. The individual deformation potential and piezoelectric interactions with the acoustic phonons are extracted using a real-space partitioning scheme. Combined with analytical considerations, we find that the piezoelectric interaction in two-dimensional (hexagonal) crystals differs qualitatively from the three-dimensional bulk form. Owing to the specific form of the piezoelectric interaction in 2D, the two coupling mechanisms are found to contribute comparably to carrier scattering throughout the considered temperature range. The calculated mobility for screened electron-phonon interaction shows a nontrivial temperature dependence both above and below the Bloch-Gruneisen temperature. In the low-temperature Bloch-Gruneisen regime the mobility approaches a mu T^6 (mu T^4) behavior for screened (unscreened) electron-phonon interaction. Very high intrinsic mobilities in excess of 10^8 cm^2 /(V s) are predicted for T < 10 K and high carrier densities (n > 10^11 cm^-2).
View original:
http://arxiv.org/abs/1206.2003
No comments:
Post a Comment