2021/10/31 by Elena Stellino, Francesco Capitani, Stellino, Elena +11
Materials Science · Engineering · #2D Materials and Applications #Chalcogenide Semiconductor Thin Films #Machine Learning in Materials Science
paper · pdf · doi:10.48550/arxiv.2111.00434
High pressure is a proven effective tool for modulating inter-layer\ninteractions in semiconducting transition metal dichalcogenides, which leads to\nsignificant band structure changes. Here, we present an extended infrared study\nof the pressure-induced semiconductor-to-metal transition in 2H-MoTe2, which\nreveals that the metallization process at 13-15 GPa is not associated with the\nindirect band gap closure, occuring at 24 GPa. A coherent picture is drawn\nwhere n-type doping levels just below the conduction band minimum play a\ncrucial role in the early metallization transition. Doping levels are also\nresponsible for the asymmetric Fano line-shape of the E1u infrared-active mode,\nwhich has been here detected and analyzed for the first time in a Transition\nMetal Dichalcogenide compound. The pressure evolution of the phonon profile\nunder pressure shows a symmetrization in the 13-15 GPa pressure range, which\noccurs simultaneously with the metallization and confirms the scenario proposed\nfor the high pressure behaviour of 2H-MoTe2.\n