Kaasbjerg, Kristen7; Thygesen, Kristian Sommer7; Jauho, Antti-Pekka7
1 Department of Physics, Technical University of Denmark2 Theoretical Atomic-scale Physics, Department of Physics, Technical University of Denmark3 Center for Atomic-scale Materials Design, Center, Technical University of Denmark4 Department of Micro- and Nanotechnology, Technical University of Denmark5 Nanointegration, Department of Micro- and Nanotechnology, Technical University of Denmark6 Theoretical Nanotechnology, Department of Micro- and Nanotechnology, Technical University of Denmark7 Center for Nanostructured Graphene, Center, Technical University of Denmark
We theoretically study the acoustic phonon limited mobility in n-doped two-dimensional MoS2 for temperatures T<100 K and high carrier densities using the Boltzmann equation and first-principles calculations of the acoustic electron-phonon (el-ph) interaction. In combination with a continuum elastic model, analytic expressions and the coupling strengths for the deformation potential and piezoelectric interactions are established. We furthermore show that the deformation potential interaction has contributions from both normal and umklapp processes and that the latter contribution is only weakly affected by carrier screening. Consequently, the calculated mobilities show a transition from a high-temperature μ~T-1 behavior to a stronger μ~T-4 behavior in the low-temperature Bloch-Grüneisen regime characteristic of unscreened deformation potential scattering. Intrinsic mobilities in excess of 105 cm2 V-1 s-1 are predicted at T<10 K and high carrier densities (n≳1011 cm-2). At 100 K, the mobility does not exceed ~7×103 cm2 V-1 s-1. Our findings provide new and important understanding of the acoustic el-ph interaction and its screening by free carriers, and is of high relevance for the understanding of acoustic phonon-limited mobilities in general.
Physical Review B (condensed Matter and Materials Physics), 2013, Vol 87, Issue 23