Superfluidity and dimerization in a multilayered system of fermionic polar molecules

TL;DR

This paper studies a layered system of fermionic polar molecules, revealing a dimerized superfluid ground state, a pseudogap phase at intermediate temperatures, and proposing light scattering for experimental detection.

Contribution

It introduces an effective Ising-XY model to describe the competition between dimerization and superfluidity in layered fermionic systems, highlighting novel phases and experimental detection methods.

Findings

Dimerized superfluid ground state with pairing between every-other layer

Existence of a dimerized pseudogap phase at intermediate temperatures

Proposal of light scattering experiments to detect dimerization

Abstract

We consider a layered system of fermionic molecules with permanent dipole moments aligned by an external field. The dipole interactions between fermions in adjacent layers are attractive and induce inter-layer pairing. Due to competition for pairing among adjacent layers, the mean-field ground state of the layered system is a dimerized superfluid, with pairing only between every-other layer. We construct an effective Ising-XY lattice model that describes the interplay between dimerization and superfluid phase fluctuations. In addition to the dimerized superfluid ground state, and high temperature normal state, at intermediate temperature, we find an unusual dimerized "pseudogap" state with only short-range phase coherence. We propose light scattering experiments to detect dimerization.