Ground states of 2D tilted dipolar bosons with density-induced hopping

TL;DR

This study explores the ground states of 2D tilted dipolar bosons in optical lattices, revealing phase transitions from superfluid to solid and supersolid phases as interaction strength and tilt angle vary.

Contribution

It provides the first detailed phase diagrams for tilted dipolar bosons with density-induced hopping, highlighting novel supersolid phases at high tilt angles.

Findings

Superfluid phase is replaced by checkerboard or stripe solid phases depending on tilt angle.

Stripe supersolid phase appears at half filling for high tilt angles.

Solid phases emerge at lower fillings as interaction strength increases.

Abstract

Motivated by recent experiments with ultracold magnetic atoms trapped in optical lattices where the orientation of atomic dipoles can be fully controlled by external fields, we study the ground state properties of dipolar bosons trapped in a two-dimensional lattice with density-induced hopping and where the dipoles are tilted along the $xz$ plane. We present ground state phase diagrams of the above system at different tilt angles. We find that, as the dipolar interaction increases, the superfluid phase at half filling factor is destroyed in favor of either a checkerboard or stripe solid phase for tilt angle $\theta \lesssim 35.3^{\circ}$ or $\theta \gtrsim 35.3^{\circ}$ respectively. More interesting physics happens at tilt angles $\theta \gtrsim 58^{\circ}$, where we find that, as the dipolar interaction strength increases, solid phases first appear at filling factor lower than $0.5$. Moreover, unlike what observed at lower tilt angles, we find that, at half filling, a stripe supersolid intervenes between the superfluid and stripe solid phase.