Topological semimetal in a fermionic optical lattice

2010/11/30 by Kai Sun, W. Vincent Liu, Andreas Hemmerich +1 · 13 citations
Materials Science · Physics and Astronomy · #Band gap #Cold Atom Physics and Bose-Einstein Condensates #Condensed matter physics #Gapless playback #Graphene research and applications #Optical lattice #Parity (physics) #Phase transition #Physics #Quantum #Quantum mechanics #Quantum phase transition #Quantum phases #Semimetal #State of matter #Symmetry protected topological order #Topological Materials and Phenomena #Topological degeneracy #Topological insulator #Topological order #Topology (electrical circuits) #cond-mat.quant-gas

paper · pdf · doi:10.1038/nphys2134

published as Nature Physics 8, 67-70 (2012) · 6 pages, 3 figures and Supplementary Information

openalex publication_date 2011/11/20 · arxiv created 2012/08/15 · arxiv updated 2012/08/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06

Abstract

Optical lattices play a versatile role in advancing our understanding of correlated quantum matter. The recent implementation of orbital degrees of freedom in chequerboard and hexagonal optical lattices opens up a new thrust towards discovering novel quantum states of matter, which have no prior analogs in solid state electronic materials. Here, we demonstrate that an exotic topological semimetal emerges as a parity-protected gapless state in the orbital bands of a two-dimensional fermionic optical lattice. The new quantum state is characterized by a parabolic band-degeneracy point with Berry flux 2π, in sharp contrast to the π flux of Dirac points as in graphene. We prove that the appearance of this topological liquid is universal for all lattices with D₄ point group symmetry as long as orbitals with opposite parities hybridize strongly with each other and the band degeneracy is protected by odd parity. Turning on inter-particle repulsive interactions, the system undergoes a phase transition to a topological insulator whose experimental signature includes chiral gapless domain-wall modes, reminiscent of quantum Hall edge states.

Citations

• Periodic table for topological insulators and superconductors
• Classification of topological insulators and superconductors in three spatial dimensions
• Topological insulators and superconductors
• Topological Insulators with Inversion Symmetry
• Sublattice Addressing and Spin-Dependent Motion of Atoms in a Double-Well Lattice
• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Electronic transport in two-dimensional graphene
• State Preparation and Dynamics of Ultracold Atoms in Higher Lattice Orbitals
• Topological Insulators
• Non-Abelian anyons and topological quantum computation

Cited by

• First-order transition into a topological superfluid state in an atom-cavity system
• Multiorbital bosons in bipartite optical lattices
• Change of an insulator's topological properties by a Hubbard interaction
• Symmetry-protected quantization and bulk-edge correspondence of massless Dirac fermions: Application to the fermionic Shastry-Sutherland model
• Emergence of superconductivity in a doped single-valley quadratic band crossing system of spin-12fermions
• Superfluid phases of fermions with hybridizedsandporbitals
• Many-body breakdown of indirect gap in topological Kondo insulators
• Orbital coupled dipolar fermions in an asymmetric optical ladder
• Engineering interaction-induced topological insulators in a3×3substrate-induced honeycomb superlattice
• Multi-Weyl Topological Semimetals Stabilized by Point Group Symmetry
• Topological phases via engineered orbital hybridization in noncentrosymmetric optical lattices
• Quantum anomalous Hall phase stabilized via realistic interactions on a kagome lattice
• Evidence of Potts-Nematic Superfluidity in a Hexagonal sp2 Optical Lattice