Spin-Twisted Optical Lattices: Tunable Flat Bands and Larkin-Ovchinnikov Superfluids
- 8 March 2021
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review Letters
- Vol. 126 (10), 103201
- https://doi.org/10.1103/physrevlett.126.103201
Abstract
Moiré superlattices in twisted bilayer graphene and transition-metal dichalcogenides have emerged as a powerful tool for engineering novel band structures and quantum phases of two-dimensional quantum materials. Here we investigate Moiré physics emerging from twisting two independent hexagonal optical lattices of atomic (pseudo-)spin states (instead of bilayers) that exhibit remarkably different physics from twisted bilayer graphene. We employ a momentum-space tight-binding calculation that includes all range real-space tunnelings and show that all twist angles can become magic and support gapped flat bands. Because of the greatly enhanced density of states near the flat bands, the system can be driven to superfluidity by weak attractive interaction. Strikingly, the superfluid phase corresponds to a Larkin-Ovchinnikov state with finite momentum pairing that results from the interplay between flat bands and interspin interactions in the unique single-layer spin-twisted lattice. Our work may pave the way for exploring novel quantum phases and twistronics in cold atomic systems.
Funding Information
- Air Force Office of Scientific Research (FA9550-16-1-0387, FA9550-20-1-0220)
- National Science Foundation (PHY-1806227)
- Army Research Office (W911NF-17-1-0128)
This publication has 70 references indexed in Scilit:
- Quantum simulations with ultracold quantum gasesNature Physics, 2012
- Moiré bands in twisted double-layer grapheneProceedings of the National Academy of Sciences of the United States of America, 2011
- Localization of Dirac Electrons in Rotated Graphene BilayersNano Letters, 2010
- Quantum Computing with Alkaline-Earth-Metal AtomsPhysical Review Letters, 2008
- Determination of Sr properties for a high-accuracy optical clockPhysical Review A, 2008
- Determination of the fermion pair size in a resonantly interacting superfluidNature, 2008
- Ultracold atomic gases in optical lattices: mimicking condensed matter physics and beyondAdvances in Physics, 2007
- Observation of the Pairing Gap in a Strongly Interacting Fermi GasScience, 2004
- Cold Bosonic Atoms in Optical LatticesPhysical Review Letters, 1998
- Simplified LCAO Method for the Periodic Potential ProblemPhysical Review B, 1954