自旋轨道耦合驱动下二维质量不相等费米气体的拓扑相

摘要

We use the mean-field theory to investigate zero temperature characteristic in a two-dimensional (2-D) mass-imbalanced Fermi gases with equal-Rashba-Dresselhaus (ERD) spin-orbit coupling (SOC) and Zeeman field.The system exists three topologically distinct superfluid phases (US-0 phase,US-1 phase,US-2 phase).Through analying the gap and atom number equations numerically,we find that superfluid order parameter can be suppressed more stronger by a Zeeman field as the mass difference increases.With increasing SOC,the weak atractive interaction region of the US-2 phase shrinks.When there is a finite SOC of the ERD type,0＜λ＜1,only in the weak atractive interaction region US-2 topologically superfluid phases exists;λ＞1,in weak and strong atractive interaction region US-2 topologically superfluid phases exists.%用平均场理论研究了二维质量不相等费米气系统的零温特性,该系统具有equal-Rashba-Dresselhaus(ERD)型自旋轨道耦合作用和Zeeman场.在该系统中存在三种不同的超流相(US-0相、US-1相、US-2相),我们通过数值分析能隙方程和粒子数方程组成的自洽方程组,发现二维费米气系统的质量相差越大,Zeeman场对超流序参量△的抑制作用就会越强.在弱吸引相互作用区域,随着自旋轨道耦合强度的增加,US-2拓扑超流相会逐渐收缩.自旋轨道耦合强度一定情况下,质量比0＜λ≤1时,只有在弱吸引相互作用区域存在US-2拓扑超流相;当质量比λ＞1时,在弱相互作用区域和强相互作用区域都存在US-2拓扑超流相.