Kristen Kaasbjerg, Kristian S. Thygesen, Karsten W. Jacobsen
In the present work we calculate the phonon-limited mobility in intrinsic
n-type single-layer MoS2 as a function of carrier density and temperature for T
> 100 K. Using a first-principles approach for the calculation of the
electron-phonon interaction, the deformation potentials and Fr\"ohlich
interaction in the isolated MoS2 layer are determined. We find that the
calculated room-temperature mobility of ~410 cm^2 V^-1 s^-1 is dominated by
optical phonon scattering via deformation potential couplings and the
Fr\"ohlich interaction with the deformation potentials to the intravalley
homopolar and intervalley longitudinal optical phonons given by 4.1 x 10^8
eV/cm and 2.6 x 10^8 eV/cm, respectively. The mobility is weakly dependent on
the carrier density and follows a \mu ~ T^-1 temperature dependence with \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, boosts the
mobility with 70 cm^2 V^-1 s^-1 and can be observed as a decrease in the
exponent to \gamma = 1.52. Our findings indicate that the intrinsic
phonon-limited mobility is approached in samples where a high-kappa dielectric
that effectively screens charge impurities is used as gate oxide.
View original:
http://arxiv.org/abs/1201.5284
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