Dimensionality-driven orthorhombic MoTe2 at room temperature

作     者：Rui He Shazhou Zhong Hyun Ho Kim Gaihua Ye Zhipeng Ye Logan Winford Daniel McHaffie Ivana Rilak Fangchu Chen Xuan Luo Yuping Sun Adam W. Tsen 

作者机构：Department of Electrical and Computer Engineering Texas Tech University Lubbock Texas 79409 USA Department of Physics University of Northern Iowa Cedar Falls Iowa 50614 USA Institute for Quantum Computing University of Waterloo Waterloo Ontario Canada N2L 3G1 Department of Physics and Astronomy University of Waterloo Waterloo Ontario Canada N2L 3G1 Department of Chemistry University of Waterloo Waterloo Ontario Canada N2L 3G1 Key Laboratory of Materials Physics Institute of Solid State Physics Chinese Academy of Sciences Hefei 230031 People's Republic of China University of Science and Technology of China Hefei 230026 China High Magnetic Field Laboratory Chinese Academy of Sciences Hefei 230031 People's Republic of China Collaborative Innovation Centre of Advanced Microstructures Nanjing University Nanjing 210093 People's Republic of China 

出 版 物：《Physical Review B》 (Phys. Rev. B)

年 卷 期：2018年第97卷第4期

页      面：041410(R)-041410(R)页

核心收录：

基　　金：National Science Foundation, NSF Canada First Research Excellence Fund, CFREF National Key Research and Development Program of China, NKRDPC, (2016YFA0300404) National Science Foundation, NSF, (DMR-1760668, DMR-1410496) Natural Sciences and Engineering Research Council of Canada, NSERC, (RGPIN-2017-03815) Chinese Academy of Sciences, CAS, (U1432139) NSF MRI, (DMR-1337207) National Natural Science Foundation of China, NSFC, (11674326) 

主　　题：Phase transitions Structural properties Topological materials Transition metal dichalcogenides Weyl semimetal Raman spectroscopy 

摘      要：We use a combination of Raman spectroscopy and transport measurements to study thin flakes of the type-II Weyl semimetal candidate MoTe2 protected from oxidation. In contrast to bulk crystals, which undergo a phase transition from monoclinic to the inversion symmetry breaking, orthorhombic phase below ∼250K, we find that in moderately thin samples below ∼12nm, a single orthorhombic phase exists up to and beyond room temperature. This could be due to the effect of c-axis confinement, which lowers the energy of an out-of-plane hole band and stabilizes the orthorhombic structure. Our results suggest that Weyl nodes, predicated upon inversion symmetry breaking, may be observed in thin MoTe2 at room temperature.