Dresden 2020 – wissenschaftliches Programm
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TT 59.9: Vortrag
Donnerstag, 19. März 2020, 17:15–17:30, HSZ 03
Controlling electronic phases in an excitonic insulator by cryogenic scanning tunneling microscopy — •Qingyu He1, Xinglu Que1, Alexander Yaresko1, Andreas Rost1,3, Masahiko Isobe1, Tomohiro Takayama1, Lihui Zhou1, and Hidenori Takagi1,2 — 1Max Planck Institute for Solid State Research, Stuttgart, Germany — 2University of Tokyo, Tokyo, Japan — 3University of St. Andrews, St. Andrews, England
The excitonic insulator is a long conjectured correlated electron phase stabilized by weakly screened electron-hole interactions. Recent intensive studies have established Ta2NiSe5 as one of the most promising candidate materials. The precise control of a many-body electronic phase with an external handle is both challenging and interesting. In our study, we realized a full and controllable phase tuning of Ta2NiSe5 from the excitonic insulator ground state to a zero-gap semiconductor state by using a tip of scanning tunneling microscope. Such dramatic reconstruction of electronic states proves the many-body nature of the gap in Ta2NiSe5, and is consistent with excitonic insulator behavior.