Condensed Matter Theory Seminar | November 25, 14:00

Tunable Stripe Order in the Moire Hubbard Model and Fragmentation of Cooper Condensates

Alex Wietek

Twisted moire materials have gained much attention since the recent discovery of superconductivity in twisted bilayer graphene. These materials offer an exciting new experimental platform to study the physics of strongly correlated electrons. The moire Hubbard model describes correlations in certain homobilayer twisted transition metal dichalcogenides. In this talk, I will present our recent results on the essential properties of this system. Using exact diagonalization and density matrix renormalization group methods, we find magnetic Mott insulating and metallic phases, which, upon doping exhibit intertwined charge and spin ordering and, in some regimes, pair binding of holes. The phases are highly tunable via an interlayer potential difference. Remarkably, the hole binding energy is found to be highly tunable revealing an experimentally accessible regime where holes become attractive. Moreover, I will present a novel approach to diagnosing superconducting Cooper condensation based on the structure of the two-body density matrix. I find that a superconducting condensate can be fragmented into partial condensates living on the charge stripes of a system. References: [1] Tunable Stripe Order and Weak Superconductivity in the Moire Hubbard Model, A. Wietek, J. Wang, J. Zang, J. Cano, A. Georges, A. Millis, Phys. Rev. Research 4, 043048 (2022) [2] Fragmented Cooper pair condensation in striped superconductors, A. Wietek, Phys. Rev. Lett. 129, 177001, Editors suggestion (2022)


MPI-PKS Dresden
Seminar Room 0.03, ETP
Contact: Simon Trebst