Intrinsic Charge Transport in Stanene: Roles of Bucklings and Electron-Phonon Couplings

TL;DR

This study investigates charge transport in stanene, revealing that buckling and electron-phonon interactions significantly influence mobility, with first-principles calculations showing lower realistic mobilities than traditional estimates.

Contribution

It provides a first-principles analysis of intrinsic charge transport in stanene, highlighting the limitations of the deformation potential approach due to buckling effects.

Findings

Intrinsic mobility at 300K is 2-3×10^3 cm^2/(V·s).

Intervalley scattering dominates carrier relaxation.

Deformation potential approach overestimates mobility by orders of magnitude.

Abstract

The intrinsic charge transport of stanene is investigated by using density function theory and density function perturbation theory coupled with Boltzmann transport equations from first principles. The accurate Wannier interpolations are applied to calculate the charge carrier scatterings with all branches of phonons with dispersion contribution. The intrinsic carrier mobilities are predicted to be 2~3$\times10^3$ cm$^2$/(V s) at 300 K, and we find that the intervalley scatterings from the out-of-plane and transverse acoustic phonon modes dominate the carrier relaxation. In contrast, the intrinsic carrier mobilities obtained by the conventional deformation potential approach (Long et al., J. Am. Chem. Soc. 2009, 131, 17728) are found to as large as 2~3$\times$10$^6$ cm$^2$/(V s) at 300 K, in which the longitudinal acoustic phonons are assumed to be the only scattering mechanism. The inadequacy of the deformation potential approximation in stanene is attributed to the buckling of the honeycomb structure, which originates from the $sp^2-sp^3$ orbital hybridization and results in broken mirror symmetry as compared to graphene. The high carrier mobility of stanene renders it a promising candidate in nanoelectronics and spintronics applications and we propose to enhance its carrier mobilities by suppressing the out-of-plane vibrations by substrate suspension or clamping.

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