High-throughput computational discovery of In2Mn2O7 as a high Curie temperature ferromagnetic semiconductor for spintronics

Wei Chen,Gian-Marco Rignanese,Geoffroy Hautier,Joel B Varley,Janine George

doi:10.1038/s41524-019-0208-x

Abstract

Materials combining strong ferromagnetism and good semiconducting properties are highly desirable for spintronic applications (e.g., in spin-filtering devices). In this work, we conduct a search for concentrated ferromagnetic semiconductors through high-throughput computational screening. Our screening reveals the limited availability of semiconductors combining ferromagnetism and a low effective mass. We identify the manganese pyrochlore oxide In2Mn2O7 as especially promising for spin transport as it combines low electron effective mass (0.29 m0), a large exchange splitting of the conduction band (1.1 eV), stability in air, and a Curie temperature (about 130 K) among the highest of concentrated ferromagnetic semiconductors. We rationalise the high performance of In2Mn2O7 by the unique combination of a pyrochlore lattice favouring ferromagnetism with an adequate alignment of O–2p, Mn–3d, and In–5s forming a dispersive conduction band while enhancing the Curie temperature.

Highlights

Materials combining semiconductivity and magnetism open up possibilities for novel electronic devices that utilise electron spin in addition to charge degrees of freedom.[1,2] Ferromagnetic semiconductors (FMSs) are in particular valued for their potential in spintronics for spin-polarised transport
Because electrons have much longer spin lifetimes than holes,[2] we focus on spin transport based on electrons as illustrated in Fig. 1, and look for FMSs with a large exchange splitting of the conduction band and a low electron effective mass
When the conduction-band character is dominated by these orbitals, their localised nature leads to a high effective mass.[41]

Summary

Introduction

Materials combining semiconductivity and magnetism open up possibilities for novel electronic devices that utilise electron spin in addition to charge degrees of freedom.[1,2] Ferromagnetic semiconductors (FMSs) are in particular valued for their potential in spintronics for spin-polarised transport. A few concentrated FMSs have been reported, including Cr halides CrBr317,18 and CrI3,19–23 Cr spinel selenides,[6] Mn pyrochlore oxides,[24] and perovskites such as BiMnO3,25 CuSeO3,26 and YTiO3.27 Among the most studied FMSs for spintronics are the Eu chalcogenides EuX (X = O,S,Se).[10,11,12,14,28] While providing very good performances in spin-filter devices, the EuX exhibit very low Curie temperature (e.g., TC = 69 K for EuO29), which is characteristic for most FMSs known to date

Methods

Results

Conclusion