Two-dimensional electron gas in a modulation-doped SrTiO3/Sr(Ti,Zr)O3 heterostructure

TL;DR

This paper demonstrates the creation of a two-dimensional electron gas in SrTiO3 through modulation doping with SrTi1-xZrxO3, using hybrid molecular beam epitaxy and magnetoresistance measurements to analyze electron behavior.

Contribution

It introduces a novel method of forming a 2DEG in SrTiO3 via modulation doping with SrTi1-xZrxO3 and provides experimental evidence with detailed magnetoresistance analysis.

Findings

Electrons transfer into SrTiO3, forming a 2DEG.

Shubnikov-de Haas oscillations depend only on perpendicular magnetic field.

Comparison of experimental oscillations with multi-subband calculations.

Abstract

A two-dimensional electron gas (2DEG) in SrTiO3 is created via modulation doping by interfacing undoped SrTiO3 with a wider-band-gap material, SrTi1-xZrxO3, that is doped n-type with La. All layers are grown using hybrid molecular beam epitaxy. Using magnetoresistance measurements, we show that electrons are transferred into the SrTiO3, and a 2DEG is formed. In particular, Shubnikov-de Haas oscillations are shown to depend only on the perpendicular magnetic field. Experimental Shubnikov-de Haas oscillations are compared with calculations that assume multiple occupied subbands.