Density Waves in Layered Systems with Fermionic Polar Molecules

TL;DR

This paper investigates how layered systems of fermionic polar molecules exhibit density-wave instabilities, revealing that multiple layers lower the critical interaction strength needed for these instabilities, especially at low densities.

Contribution

It demonstrates that the presence of multiple layers reduces the critical interaction strength for density-wave formation, with phase relationships between layers analyzed.

Findings

Critical density-wave instability strength decreases with more layers.

In-phase density waves are the lowest energy configuration.

The parameter regime is accessible with current experimental setups.

Abstract

A layered system of two-dimensional planes containing fermionic polar molecules can potentially realize a number of exotic quantum many-body states. Among the predictions, are density-wave instabilities driven by the anisotropic part of the dipole-dipole interaction in a single layer. However, in typical multilayer setups it is reasonable to expect that the onset and properties of a density-wave are modified by adjacent layers. Here we show that this is indeed the case. For multiple layers the critical strength for the density-wave instability decreases with the number of layers. The effect depends on density and is more pronounced in the low density regime. The lowest solution of the instability corresponds to the density waves in the different layers being in-phase, whereas higher solutions have one or several adjancet layers that are out of phase. The parameter regime needed to explore this instability is within reach of current experiments.