Bond order solid of two-dimensional dipolar fermions

TL;DR

This paper theoretically explores the phase diagram of two-dimensional dipolar fermions on a square lattice, revealing new bond-ordered phases with potential experimental realization.

Contribution

It identifies and characterizes two novel bond order phases in dipolar fermion systems, expanding understanding of possible quantum phases with long-range interactions.

Findings

Discovery of two new bond order phases with periodic kinetic energy modulations.

Demonstration that these phases can be realized with current experimental techniques.

Mapping of the phase diagram including superfluid, charge density wave, and bond order phases.

Abstract

Recent experimental realization of dipolar Fermi gases near or below quantum degeneracy provides opportunity to engineer Hubbard-like models with long range interactions. Motivated by these experiments, we chart out the theoretical phase diagram of interacting dipolar fermions on the square lattice at zero temperature and half filling. We show that in addition to p-wave superfluid and charge density wave order, two new and exotic types of bond order emerge generically in dipolar fermion systems. These phases feature homogeneous density but periodic modulations of the kinetic hopping energy between nearest or next-nearest neighbors. Similar, but manifestly different, phases of two-dimensional correlated electrons have previously only been hypothesized and termed "density waves of nonzero angular momentum". Our results suggest that these phases can be constructed flexibly with dipolar fermions, using currently available experimental techniques.