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Institute for Condensed Matter Theory Seminar: Topology and Interactions: Emergent Mottness at Quarter filling in the Haldane and KM/BHZ models

Event Type
The Institute for Condensed Matter Theory
190 ESB
Oct 10, 2022   12:00 pm  
Philip Phillips, University of Illinois Urbana Champaign
Janice K Benner
Originating Calendar
Physics - Institute for Condensed Matter Theory Seminar

While the recent advances in topology have led to a classification scheme for electronic bands described by the standard theory of metals, a similar     scheme has not emerged for strongly correlated systems such as Mott insulators in which a partially filled band carries no current.  This talk will address this deficiency by including interactions into the three dominant models for topological states, the Haldane and KM/BHZ models.  We show that all of these models

             possess a quarter-filled state that is an insulator once the interactions exceed the bandwidth.  We obtain this result by solving analytically a model in which the interactions are local in momentum space and then numerically by quantum Monte Carlo simulations on the corresponding Hubbard model.  Both yield the same result: For sufficiently large interaction strengths, the quarter-filled Haldane/KM/BHZ models form a topological Mott insulator with ferromagentic correlations with a Chern number of unity.  Recent experiments on the anomalous quantum Hall effect in transition metal dichalcogenides are discussed in this context.

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