Emergence of Metallic Quantum Solid Phase in a Rydberg-Dressed Fermi Gases

TL;DR

This paper predicts a novel metallic quantum solid phase in a Rydberg-dressed Fermi gas, characterized by a self-assembled density wave with a Fermi surface, emerging at low temperatures due to roton instability.

Contribution

It introduces the concept of a metallic density wave state in a Rydberg-dressed Fermi gas, combining Fermi surface and crystal order, which is a new phase not previously observed.

Findings

Roton minimum softens at a critical density

A metallic density wave state emerges at low temperatures

Critical temperature is about one-tenth of the Fermi energy

Abstract

We examine possible low-temperature phases of a repulsively Rydberg-dressed Fermi gas in a three-dimensional free space. It is shown that the collective density excitations develop a roton minimum, which is softened at a wavevector smaller than the Fermi wavevector when the particle density is above a critical value. The mean field calculation shows that unlike the insulating charge density waves states often observed in conventional condensed matters, a self-assembled metallic density wave state emerges at low temperatures. In particular, the density wave state supports a Fermi surface and a body-center-cubic crystal order at the same time with the estimated critical temperature being about one-tenth of the non-interacting Fermi energy. Our results suggest the emergency of a fermionic quantum solid that should be observable in current experimental setup.