Electron quantum interference in epitaxial antiferromagnetic NiO thin films

Jia Xu,Feng Lou,Andreas K Schmid,Hongjun Xiang,Qian Li,Chao Zhou,Gong Chen,Mengwen Jia,Kai Liu,Yizheng Wu

doi:10.1063/1.5129772

Abstract

The electron reflectivity from NiO thin films grown on Ag(001) has been systematically studied as a function of film thickness and electron energy. A strong electron quantum interference effect was observed from the NiO film, which is used to derive the unoccupied band dispersion above the Fermi surface along the Γ−X direction using the phase accumulation model. The experimental bands agree well with first-principles calculations. A weaker electron quantum interference effect was also observed from the CoO film.

Highlights

Antiferromagnetic (AFM) spintronics has drawn significant attention due to its potential for low power consumption information storage and ultrafast switching.1,2 NiO, one of the most common AFM oxides, is a fascinating candidate for investigating many novel spin-dependent phenomena in AFM materials, such as spin Hall magnetoresistance,3–6 enhanced spin current transmission,7–10 THz magnons,11,12 and the switching of AFM spins by the spin-orbit torque.13–15 All those spin-dependent transport properties are closely correlated with the electronic structure of NiO, which motivates experimental studies of band dispersions, especially in the ultrathin film range.Theoretically, the NiO band structure has been intensively studied
We find that the electron reflectivity from NiO films oscillates with both electron energy and film thickness
In the quantum interference measurements, the incident electron beam is normal to the thin film surface, and the electron reflectivity is measured as a function of the film thickness and electron energy

Summary

Introduction

Antiferromagnetic (AFM) spintronics has drawn significant attention due to its potential for low power consumption information storage and ultrafast switching. NiO, one of the most common AFM oxides, is a fascinating candidate for investigating many novel spin-dependent phenomena in AFM materials, such as spin Hall magnetoresistance, enhanced spin current transmission, THz magnons, and the switching of AFM spins by the spin-orbit torque. All those spin-dependent transport properties are closely correlated with the electronic structure of NiO, which motivates experimental studies of band dispersions, especially in the ultrathin film range.Theoretically, the NiO band structure has been intensively studied. NiO, one of the most common AFM oxides, is a fascinating candidate for investigating many novel spin-dependent phenomena in AFM materials, such as spin Hall magnetoresistance, enhanced spin current transmission, THz magnons, and the switching of AFM spins by the spin-orbit torque.. NiO, one of the most common AFM oxides, is a fascinating candidate for investigating many novel spin-dependent phenomena in AFM materials, such as spin Hall magnetoresistance, enhanced spin current transmission, THz magnons, and the switching of AFM spins by the spin-orbit torque.13–15 All those spin-dependent transport properties are closely correlated with the electronic structure of NiO, which motivates experimental studies of band dispersions, especially in the ultrathin film range. Due to the promising applications of NiO films in AFM spintronics, it is important to study the unoccupied electronic structure of NiO ultrathin film, which can help to refine the knowledge of the unoccupied band structures above the Fermi energy

Methods

Results

Conclusion