Publication

Metal-insulator transition at low densities in a two-dimensional low-bandgap semiconductor

2026

Abstract

and contact resistances as low as 1.31 kΩ·μm at 1.5 K. These characteristics enable a gate-tunable metal-insulator transition at carrier densities down to 2.75 × 10¹⁰ cm⁻². Transport in this regime is dominated by electron-electron interactions, as supported by finite-temperature scaling. Below 50 K, however, an additional disorder-related energy scale emerges, consistent with percolation. These results demonstrate that disorder remains relevant even in high-mobility devices, challenging a purely interaction-driven transition in two-dimensional systems.

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2026

Abstract

Official source

Related concepts (32)

Semimetal

A semimetal is a material with a very small overlap between the bottom of the conduction band and the top of the valence band. According to electronic band theory, solids can be classified as insulators, semiconductors, semimetals, or metals. In insulators and semiconductors the filled valence band is separated from an empty conduction band by a band gap. For insulators, the magnitude of the band gap is larger (e.g., > 4 eV) than that of a semiconductor (e.g., < 4 eV).

High-electron-mobility transistor

A high-electron-mobility transistor (HEMT or HEM FET), also known as heterostructure FET (HFET) or modulation-doped FET (MODFET), is a field-effect transistor incorporating a junction between two materials with different band gaps (i.e. a heterojunction) as the channel instead of a doped region (as is generally the case for a MOSFET). A commonly used material combination is GaAs with AlGaAs, though there is wide variation, dependent on the application of the device.

Mott insulator

Mott insulators are a class of materials that are expected to conduct electricity according to conventional band theories, but turn out to be insulators (particularly at low temperatures). These insulators fail to be correctly described by band theories of solids due to their strong electron–electron interactions, which are not considered in conventional band theory. A Mott transition is a transition from a metal to an insulator, driven by the strong interactions between electrons.

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Metal-insulator transition at low densities in a two-dimensional low-bandgap semiconductor

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