Transport properties of two-dimensional electron systems on silicon (111) surfaces

TL;DR

This paper theoretically investigates the transport properties of a two-dimensional electron system on hydrogen-passivated Si(111) surfaces, showing that impurity scattering and valley degeneracy significantly influence mobility and resistivity.

Contribution

It provides a detailed theoretical analysis of transport in Si(111) 2D electron systems, highlighting the role of impurity scattering and valley degeneracy in experimental observations.

Findings

Screened charged impurity scattering dominates transport.

Valley degeneracy g_v=2 aligns better with experiments.

Theoretical results agree with experimental mobility and resistivity data.

Abstract

We theoretically study transport properties of a two-dimensional electron system on a hydrogen-passivated Si(111) surface in the field-effect-transistor (FET) configuration. We calculate the density and temperature dependent mobility and resistivity for the recently fabricated Si(111)-vacuum FET by using a semiclassical Boltzmann theory including screened charged impurity scattering. We find reasonable agreement with the corresponding experimental transport properties, indicating that the screened disorder potential from random charged impurities is the main scattering mechanism. We also find that the theoretical results with the valley degeneracy $g_v=2$ give much better agreement with experiment than the $g_v=6$ situation indicating that the usual bulk six-valley degeneracy of Si is lifted in this system.