Orbital Selective Mott Transition in Thin Film VO2
Department of Physics, Applied Physics, and Astronomy, Binghamton University – SUNY
In this talk, evidences of strain-induced modulation of electron correlation effects in the rutile phase of epitaxial VO2/TiO2 will be presented. The strain is engineered by different growth orientations (001), (100), and (110). We find that the hard x-ray photoelectron spectroscopy (HAXPES) reveals significant suppression of the density of states at the Fermi energy in (100) and (110) samples at a temperature well above the metal-insulator transition temperature, but not in the (001) sample. Moreover, the soft V L-edge x-ray absorption spectroscopy indicates that suppression of the density of states at Fermi energy is accompanied by an increasing preferential filling in one particular d orbital of vanadate (V). Using the density functional theory implemented with the slave spin method, we show that all these findings can be well understood as an orbital selective Mott phase in which some orbital is Mott insulating while others remain itinerant. Implications of our results will be discussed.
Host: Harsh Mathur