2H-and 1T′-phase monolayer MoTe2 films on highly oriented pyrolytic graphite are studied using scanning tunneling microscopy and spectroscopy（STM/STS）.The phase transition of MoTe2 can be controlled by a postgrowth...2H-and 1T′-phase monolayer MoTe2 films on highly oriented pyrolytic graphite are studied using scanning tunneling microscopy and spectroscopy（STM/STS）.The phase transition of MoTe2 can be controlled by a postgrowth annealing process,and the intermediate state during the phase transition is directly observed by STM.For 2H-MoTe2,inversion domain boundaries are presented as bright lines at high sample bias,but as dark lines at lower sample bias.The dI/dV mappings reveal the distinct distributions of electronic states between domain boundaries and interiors of domains.It sihould be noted that a 2×2 periodic structure is clearlfy discernable inside the domains,where the STS measurement shows a small dip of size～150 meV at the vicinity of the Fermi level,indicating that the 2×2 periodic structure may be an incommensurate charge density wave.Moreover,a4×4 periodic structure appears in 2H-MoTe2 grown at a higher substrate temperature.展开更多
基金Supported by the National Key Research and Development Program of China under Grant Nos 2016YFA0301003 and 2016YFA0300403the National Natural Science Foundation of China under Grant Nos 11521404,11634009,U1632102,11504230,11674222,11574202,11674226,11574201 and U1632272
文摘2H-and 1T′-phase monolayer MoTe2 films on highly oriented pyrolytic graphite are studied using scanning tunneling microscopy and spectroscopy（STM/STS）.The phase transition of MoTe2 can be controlled by a postgrowth annealing process,and the intermediate state during the phase transition is directly observed by STM.For 2H-MoTe2,inversion domain boundaries are presented as bright lines at high sample bias,but as dark lines at lower sample bias.The dI/dV mappings reveal the distinct distributions of electronic states between domain boundaries and interiors of domains.It sihould be noted that a 2×2 periodic structure is clearlfy discernable inside the domains,where the STS measurement shows a small dip of size～150 meV at the vicinity of the Fermi level,indicating that the 2×2 periodic structure may be an incommensurate charge density wave.Moreover,a4×4 periodic structure appears in 2H-MoTe2 grown at a higher substrate temperature.
