Antifferomagnetic FeSe monolayer on SiTiO$_{3}$: The charge doping and electric field effects

TL;DR

This paper theoretically investigates the electronic structure of an antiferromagnetic FeSe monolayer on SrTiO3, revealing charge transfer, electric field effects, and the potential for an electron-hole bilayer system.

Contribution

It introduces a detailed theoretical analysis of AFM FeSe monolayer on SrTiO3, including a tight-binding model and insights into charge transfer and electric field effects.

Findings

Disappearance of Fermi surface around BZ center explained by AFM phase

Significant charge transfer from substrate to FeSe monolayer

Electric field distorts spin-resolved bands at BZ corner

Abstract

We present theoretically the electronic structure of antiferromagnetic (AFM) FeSe monolayer on TiO$_{2}$ terminated SrTiO$_{3}$(001) surface. It is revealed that the striking disappearance of the Fermi surface around the Brillouin zone (BZ) center can be well explained by the antiferromatnetic (AFM) phase. We show that the system has a considerable charge transfer from SrTiO$_{3}$(001) substrate to FeSe monolayer, and so has a self-constructed electric field. The FeSe monolayer band structure near the BZ center is sensitive to charge doping, and the spin-resolved energy bands at BZ corner are distorted to be flattened by the perpendicular electric field. We propose a tight-binding model Hamiltonian to take these key factors into account. We also show that this composite structure is an ideal electron-hole bilayer system, with electrons and holes respectively formed in FeSe monolayer and TiO$_{2}$ surface layer.