Strain-Induced Room-Temperature Ferromagnetic Semiconductors with LargeStrain-Induced Room-Temperature Ferromagnetic Semiconductors with LargeAnomalous Hall Conductivity in Two-Dimensional Cr2Ge2Se6

Xue-Juan Dong,1 Jing-Yang You,1 Bo Gu,2,3,* and Gang Su1,2,3,†

1School of Physical Sciences, University of Chinese Academy of Sciences, 100049 Beijing, China1School of Physical Sciences, University of Chinese Academy of Sciences, 100049 Beijing, China2Kavli Institute for Theoretical Sciences, and CAS Center for Excellence in Topological Quantum Computation,University of Chinese Academy of Sciences, 100190 Beijing, China3Physical Science Laboratory, Huairou National Comprehensive Science Center, 101400 Beijing, China

By density-functional-theory calculations, we predict a stable two-dimensional (2D) ferromagneticBy density-functional-theory calculations, we predict a stable two-dimensional (2D) ferromagneticsemiconductor, Cr2Ge2Se6, where the Curie temperature TC can be dramatically increased beyond roomtemperature by applying a few-percent strain. In addition, the anomalous Hall conductivity in 2DCr2Ge2Se6 and Cr2Ge2Te6 is predicted to be comparable to that in the ferromagnetic metals Fe and Ni,and is an order of magnitude larger than that in the diluted magnetic semiconductor Ga(Mn,As). Basedon superexchange interactions, the increased TC in 2D Cr2Ge2Se6 caused by strain can be understood bythe decreased energy difference between 3d orbitals of Cr and 4p orbitals of Se. Our findings highlight themicroscopic mechanism to obtain room-temperature ferromagnetic semiconductors by strain.