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Phonon-limited mobility in n -type single-layer MoS 2 from first principles

2012; American Physical Society; Volume: 85; Issue: 11 Linguagem: Inglês

10.1103/physrevb.85.115317

1550-235X

Kristen Kaasbjerg, Kristian S. Thygesen, Karsten W. Jacobsen,

Transition Metal Oxide Nanomaterials

We study the phonon-limited mobility in intrinsic $n$-type single-layer MoS${}_{2}$ for temperatures $T>100$ K. The materials properties including the electron-phonon interaction are calculated from first principles and the deformation potentials and Fr\"ohlich interaction in single-layer MoS${}_{2}$ are established. The calculated room-temperature mobility of $\ensuremath{\sim}$410 cm${}^{2}$V${}^{\ensuremath{-}1}$s${}^{\ensuremath{-}1}$ is found to be dominated by optical phonon scattering via intra and intervalley deformation potential couplings and the Fr\"ohlich interaction. The mobility is weakly dependent on the carrier density and follows a $\ensuremath{\mu}\ensuremath{\sim}{T}^{\ensuremath{-}\ensuremath{\gamma}}$ temperature dependence with $\ensuremath{\gamma}=1.69$ at room temperature. It is shown that a quenching of the characteristic homopolar mode, which is likely to occur in top-gated samples, increases the mobility with $\ensuremath{\sim}$70 cm${}^{2}$V${}^{\ensuremath{-}1}$s${}^{\ensuremath{-}1}$ and can be observed as a decrease in the exponent to $\ensuremath{\gamma}=1.52$. In comparison to recent experimental findings for the mobility in single-layer MoS${}_{2}$ ($\ensuremath{\sim}$200 cm${}^{2}$V${}^{\ensuremath{-}1}$s${}^{\ensuremath{-}1}$), our results indicate that mobilities close to the intrinsic phonon-limited mobility can be achieved in two-dimensional materials via dielectric engineering that effectively screens static Coulomb scattering on, e.g., charged impurities.