Field effect on surface states in a doped Mott-Insulator thin film

TL;DR

This study explores how surface states in doped Mott-insulator thin films are affected by electric fields, revealing significant changes in quasiparticle weights that could impact device applications.

Contribution

It introduces an inhomogeneous Gutzwiller approach to analyze surface effects and electric field influences in doped Mott-insulator thin films, highlighting new surface state behaviors.

Findings

Quasiparticle weight recovers exponentially into the slab at low doping.

Friedel oscillations emerge near the surface with increased doping.

Electric fields cause large variations in quasiparticle weights, up to five orders of magnitude.

Abstract

Surface effects of a doped thin film made of a strongly correlated material are investigated both in the absence and presence of a perpendicular electric field. We use an inhomogeneous Gutzwiller approximation for a single band Hubbard model in order to describe correlation effects. For low doping, the bulk value of the quasiparticle weight is recovered exponentially deep into the slab, but with increasing doping, additional Friedel oscillations appear near the surface. We show that the inverse correlation length has a power-law dependence on the doping level. In the presence of an electrical field, considerable changes in the quasiparticle weight can be realized throughout the system. We observe a large difference (as large as five orders of magnitude) in the quasiparticle weight near the opposite sides of the slab. This effect can be significant in switching devices that use the surface states for transport.