Condensed Matter Theory Seminar - Valentin Crepel - “Chiral anomaly for quantum anomalous phases in twisted transition metal dichalcogenides”

Event time: 
Thursday, September 21, 2023 - 1:00pm to 2:00pm
Sloane Physics Laboratory (SPL), Room 51 See map
217 Prospect Street
New Haven, CT 06511
Event description: 

The analog of fractional quantum Hall states in absence of applied magnetic field, fractional Chern insulators, have recently been observed in twisted homobilayers of MoTe2.
Theoretically, this ground-breaking discovery is understood as the result of interactions within a flat band with non-trivial spin Chern number. However, and as opposed to twisted bilayer graphene, arguments ensuring the existence of such flat topological band lack in transition metal dichalcogenides. Furthermore, the question of how this phase can arise in systems subject to large lattice deformations and non-negligible twist angle variations has received little attention.
In this talk, I will present argument that clearly demonstrate why a magic-angle and a topological flat band necessarily exist in twisted transition metal dichalcogenides, and explains how a chiral anomaly protects the observed quantum anomalous Hall physics against experimental imperfections.