Surface roughness scattering in multisubband accumulation layers

Abstract

Accumulation layers with very large concentrations of electrons where many subbands are filled became recently available due to ionic liquid and other new methods of gating. The low temperature mobility in such layers is limited by the surface roughness scattering. However theories of roughness scattering so far dealt only with the small-density single subband two-dimensional electron gas (2DEG). Here we develop a theory of roughness-scattering limited mobility for the multisubband large concentration case. We show that with growing 2D electron concentration $n$ the surface dimensionless conductivity $\sigma /(2e^2/h)$ first decreases as $\propto n^{-6/5}$ and then saturates as $\sim (d{a}_B/{\Delta }^2)\gg 1$, where $d$ and $\Delta$ are the characteristic length and height of the surface roughness, $a_B$ is the effective Bohr radius. This means that in spite of the shrinkage of the 2DEG width and the related increase of the scattering rate, the 2DEG remains a good metal. Thus, there is no re-entrant metal-insulator transition at high concentrations conjectured by Das Sarma and Hwang [PRB 89, 121413 (2014)].

A few corrections to the version published in PRB are included here in this version

References in corpus (6)

• Controlling electron-phonon interactions in graphene at ultra high carrier densities
• Accumulation, inversion, and depletion layers in SrTiO${}_3$
• Correlation between metal-insulator transitions and structural distortions in high-electron-density SrTiO3 quantum wells
• Multiband Transport in Bilayer Graphene at High Carrier Densities
• Short-range disorder effects on electronic transport in 2D semiconductor structures
• Metallic State of Low Mobility Silicon at High Carrier density induced by an Ionic Liquid

Cited by in corpus (6)

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• Direct Observation of Long-range field-effect from gate tuning of non-local conductivity
• Semiclassical theory of anisotropic transport at LaAlO3/SrTiO3 interfaces under in-plane magnetic field
• Anomalous conductivity, Hall factor, magnetoresistance, and thermopower of accumulation layer in ${\text{SrTiO}}_3$
• Repairing the Surface of InAs-based Topological Heterostructures
• Roughness scattering induced insulator-metal-insulator transition in a quantum wire