Tunable spin superstripe phase with a long period and high visibility
Xi-Wang Luo, Chuanwei Zhang
Abstract
Recent experimental observation of superstripe phases in double well optical lattices with Raman-assisted tunneling using Bragg reflection opens a new avenue for exploring supersolids, exotic quantum matters possessing both crystalline structure and superfluidity. However, direct real-space detection of a superstripe is still challenging in experiments because of its short period and low visibility. Here we propose a scheme for generating a spin superstripe phase [i.e., only spin (no total) density modulation] with a long period ($\sim $5 $\mu $m) and high visibility ($\sim $100%) in a spin-orbit coupled BEC, which can be directly observed in the real-space. In the scheme, two hyperfine spin states are individually Raman coupled with a largely-detuned third state, which induce a momentum-space separation between two lower band dispersions, yielding an effective spin-1/2 system with tunable spin-orbit coupling and Zeeman fields. Without effective Zeeman fields, spin-dependent interaction dominates, yielding a spin superstripe phase with a long tunable period and high visibility. Our scheme provides a platform for realizing and observing exotic properties of superstripe phases as well as exploring novel physics with tunable spin-orbit coupling.