Density-wave phases of dipolar fermions in a bilayer

TL;DR

This paper explores the phase diagram of dipolar fermions in a bilayer system, revealing a quantum phase transition between different density wave phases driven by interactions and geometry.

Contribution

It introduces a theoretical analysis of density-wave instabilities in bilayer dipolar fermions using adapted linear response theory, highlighting a new phase transition.

Findings

Bilayer geometry stabilizes a new density wave phase.

Identification of a quantum phase transition between stripe phases.

Density-wave instabilities depend on interlayer interactions.

Abstract

We investigate the phase diagram of dipolar fermions with aligned dipole moments in a two-dimensional (2D) bilayer. Using a version of the Singwi-Tosi-Land-Sjolander scheme recently adapted to dipolar fermions in a single layer [M. M. Parish and F. M. Marchetti, Phys. Rev. Lett. 108, 145304 (2012)], we determine the density-wave instabilities of the bilayer system within linear response theory. We find that the bilayer geometry can stabilize the collapse of the 2D dipolar Fermi gas with intralayer attraction to form a new density wave phase that has an orientation perpendicular to the density wave expected for strong intralayer repulsion. We thus obtain a quantum phase transition between stripe phases that is driven by the interplay between strong correlations and the architecture of the low dimensional system.