One-dimensional electron gas in strained lateral heterostructures of single layer materials

O Rubel

doi:10.1038/s41598-017-03880-w

Abstract

Confinement of the electron gas along one of the spatial directions opens an avenue for studying fundamentals of quantum transport along the side of numerous practical electronic applications, with high-electron-mobility transistors being a prominent example. A heterojunction of two materials with dissimilar electronic polarisation can be used for engineering of the conducting channel. Extension of this concept to single-layer materials leads to one-dimensional electron gas (1DEG). MoS2/WS2 lateral heterostructure is used as a prototype for the realisation of 1DEG. The electronic polarisation discontinuity is achieved by straining the heterojunction taking advantage of dissimilarities in the piezoelectric coupling between MoS2 and WS2. A complete theory that describes an induced electric field profile in lateral heterojunctions of two-dimensional materials is proposed and verified by first principle calculations.

Highlights

Confinement of electrons along one of the spatial directions results in a two-dimensional electron gas (2DEG) that exhibits interesting physical phenomena along the side of useful technological applications
It will be shown that a lateral heterojunction of 2D materials with dissimilar piezoelectric properties can be used to achieve additional confinement of charge carriers along the interface, which creates conditions for realisation of a one-dimensional electron gas (1DEG)
We will use an ab initio model to explore the feasibility of achieving conditions for 1D confinement of charge carriers in a lateral heterojunction of two single-layer materials

Summary

Conclusions

One-dimensional conductivity channel is obtained in a lateral MoS2/WS2 heterojunction. Conducting electronic states are confined along the interface by an inhomogeneous electric field that is induced by differences in the piezoelectric and elastic response of two materials thereby creating a one-dimensional electron gas. An effective model that captures interactions between electric and elastic degrees of freedom in low-dimensional heterostructures is developed. The model accurately predicts the magnitude of macroscopic electric field induced in the strained heterostructure as verified by ab initio calculations. This realisation of 1D electron gas creates an alternative to a quasi 1D conducting channel formed in the 2D electron gas of GaAs/(AlGa)As heterostructures by electrostatic gating[22, 23] that can be potentially used for low-power switching applications

Methods

Findings

Additional Information