Strong spin-lattice coupling in CrSiTe3

L D Casto,M.-W Lin,K Xiao,T J Williams,B C Sales,J.-Q Yan,M O Yokosuk,R G Hennig,H L Zhuang,J L Musfeldt,D Mandrus,A J Clune

doi:10.1063/1.4914134

Abstract

CrSiTe3 has attracted recent interest as a candidate single-layer ferromagnetic semiconductor, but relatively little is known about the bulk properties of this material. Here, we report single-crystal X-ray diffraction, magnetic properties, thermal conductivity, vibrational, and optical spectroscopies and compare our findings with complementary electronic structure and lattice dynamics principles calculations. The high temperature paramagnetic phase is characterized by strong spin-lattice interactions that give rise to glassy behavior, negative thermal expansion, and an optical response that reveals that CrSiTe3 is an indirect gap semiconductor with indirect and direct band gaps at 0.4 and 1.2 eV, respectively. Measurements of the phonons across the 33 K ferromagnetic transition provide additional evidence for strong coupling between the magnetic and lattice degrees of freedom. The Si-Te stretching and Te displacement modes are sensitive to the magnetic ordering transition, a finding that we discuss in terms of the superexchange mechanism. Spin-lattice coupling constants are also extracted.

Highlights

CrSiTe3 has attracted recent interest as a candidate single-layer ferromagnetic semiconductor, but relatively little is known about the bulk properties of this material
The high temperature paramagnetic phase is characterized by strong spin-lattice interactions that give rise to glassy behavior, negative thermal expansion, and an optical response that reveals that CrSiTe3 is an indirect gap semiconductor with indirect and direct band gaps at 0.4 and 1.2 eV, respectively
Even the highest TC “pnictide” superconductor is a chalcogenide: single layers of FeSe have been found to superconduct with transition temperatures greater than 100 K.4

Summary

Introduction

CrSiTe3 has attracted recent interest as a candidate single-layer ferromagnetic semiconductor, but relatively little is known about the bulk properties of this material. We report single-crystal X-ray diffraction, magnetic properties, thermal conductivity, vibrational, and optical spectroscopies and compare our findings with complementary electronic structure and lattice dynamics principles calculations. The high temperature paramagnetic phase is characterized by strong spin-lattice interactions that give rise to glassy behavior, negative thermal expansion, and an optical response that reveals that CrSiTe3 is an indirect gap semiconductor with indirect and direct band gaps at 0.4 and 1.2 eV, respectively.

Results

Conclusion