Regensburg 2025 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 43: Twisted Materials / Systems (joint session TT/HL)

HL 43.5: Talk

Wednesday, March 19, 2025, 18:00–18:15, H31

Mott transitions and doping asymmetry in twisted bilayer WSe₂ — •Siheon Ryee¹, Lennart Klebl^2,1, Valentin Crépel³, Ammon Fischer⁴, Lede Xian^5,6, Angel Rubio^6,3, Dante Kennes^4,6, Andrew Millis^3,7, Antoine Georges^8,3, Roser Valentí⁹, and Tim Wehling¹ — ¹University of Hamburg, Hamburg, Germany — ²University of Würzburg, Würzburg, Germany — ³Flatiron Institute, New York, USA — ⁴RWTH Aachen University, Aachen, Germany — ⁵Tsientang Institute for Advanced Study, Zhejiang, China — ⁶Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany — ⁷Columbia University, New York, USA — ⁸Collège de France, Paris, France — ⁹Goethe Universität Frankfurt, Frankfurt am Main, Germany

The recent discovery of superconductivity in twisted bilayer WSe₂ (tWSe₂) at two distinct twist angles (3.65 deg and 5 deg) along with previous reports of metal-insulator transitions, spin density wave states, and fractional Chern insulators raises deep questions in correlated electron physics. We present results of a dynamical mean-field theory-based investigation of a model that faithfully captures the band structure and topology of twisted transition metal dichalcogenides as functions of twist angle and displacement field. We find good agreement with several key aspects of the experimental data. Focusing further on the twist angle of 3.65 deg, we discuss the nature of the electric-field-induced metal-insulator transition, the experimentally observed coherence temperature, and the origin of the observed doping asymmetry in resistivity.

Keywords: twisted transition metal dichalcogenides; metal-insulator transition; superconductivity; correlated electron materials; dynamical mean-field theory