Strongly metallic electron and hole 2D transport in an ambipolar Si-vacuum field effect transistor

Abstract

We report experiment and theory on an ambipolar gate-controlled Si-vacuum field effect transistor (FET) where we study electron and hole (low-temperature 2D) transport in the same device simply by changing the external gate voltage to tune the system from being a 2D electron system at positive gate voltage to a 2D hole system at negative gate voltage. The electron (hole) conductivity manifests strong (moderate) metallic temperature dependence with the conductivity decreasing by a factor of 8 (2) between 0.3 K and 4.2 K with the peak electron mobility ($\sim 18$ m${}^2$/Vs) being roughly 20 times larger than the peak hole mobility (in the same sample). Our theory explains the data well using RPA screening of background Coulomb disorder, establishing that the observed metallicity is a direct consequence of the strong temperature dependence of the effective screened disorder.

5 pages, 3 figures

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Cited by in corpus (4)

• Electronic hydrodynamics and the breakdown of the Wiedemann-Franz and Mott laws in interacting metals
• Screening and transport in 2D semiconductor systems at low temperatures
• Density-tuned effective metal-insulator transitions in 2D semiconductor layers: Anderson localization or Wigner crystallization
• Understanding disorder in Silicon quantum computing platforms: Scattering mechanisms in Si/SiGe quantum wells