Low temperature metallic state induced by electrostatic carrier doping of SrTiO$_3$

TL;DR

This study demonstrates an insulator-to-metal transition in SrTiO3 induced by electrostatic doping, showing metallic behavior at low temperatures with high mobility, using field-effect transistors with organic gate insulators.

Contribution

It provides experimental evidence of a low-temperature metallic state in SrTiO3 controlled purely by electrostatic carrier doping, a novel approach for tuning electronic phases.

Findings

Sheet resistance drops below 10 kΩ at low temperatures.

Carrier mobility exceeds 1000 cm²/Vs.

Metallic behavior observed with positive temperature coefficient of resistance.

Abstract

Transport properties of SrTiO$_3$-channel field-effect transistors with parylene organic gate insulator have been investigated. By applying gate voltage, the sheet resistance falls below $R_{\Box}$ $\sim$ 10 k$\Omega$ at low temperatures, with carrier mobility exceeding 1000 cm$^2$/Vs. The temperature dependence of the sheet resistance taken under constant gate voltage exhibits metallic behavior ($dR$/$dT$ $>$ 0). Our results demonstrate an insulator to metal transition in SrTiO$_3$ driven by electrostatic carrier density control.