Abstract
Motivated by recent experimental development, we investigate spin–orbit coupled repulsive Fermi atoms in a one-dimensional optical lattice. Using the density-matrix renormalization group method, we calculate the momentum distribution function, gap, and spin-correlation function to reveal rich ground-state properties. We find that spin–orbit coupling (SOC) can generate unconventional momentum distribution, which depends crucially on the filling. We call the corresponding phase with zero gap the SOC-induced metallic phase. We also show that SOC can drive the system from the antiferromagnetic to ferromagnetic Mott insulators with spin rotating. As a result, a second-order quantum phase transition between the spin-rotating ferromagnetic Mott insulator and the SOC-induced metallic phase is predicted at the strong SOC. Here spin rotating means the spin orientations of the nearest-neighbor sites are not parallel or antiparallel, i.e., they have an intersection angle Finally, we show that the momentum kpeak, at which the peak of the spin-structure factor appears, can also be affected dramatically by SOC. The analytical expression of this momentum with respect to the SOC strength is also derived, which suggests that the predicted spin-rotating ferromagnetic (kpeak < π /2 ) and antiferromagnetic (π /2 < kpeak < π) correlations can be detected experimentally by measuring the SOC-dependent spin-structure factor via time-of-flight imaging.
Highlights
A second-order quantum phase transition between the spinrotating ferromagnetic Mott insulator and the spin-orbit coupling (SOC)-induced metallic phase is predicted at the strong SOC
Based on the predicted properties of the momentum distribution, the gap, and the spin correlation, we find that the homogeneous Hamiltonian (3) has five phases, including the metallic phase, the SOC-induced metallic phase, the antiferromagnetic Mott insulator, the spin-rotating antiferromagnetic Mott insulator, and the spin-rotating ferromagnetic Mott insulator, at the half filling (n = 1)
We find that the transitions between the metallic phase and the antiferromagnetic Mott insulator, between the SOC-induced metallic phase and the spinrotating antiferromagnetic Mott insulator, and between the SOC-induced metallic phase and the spin-rotating ferromagnetic Mott insulator are of second order, because the second-order derivative of the ground-state energy is discontinuous at the critical points
Summary
Ultracold Fermi atoms in optical lattices have attracted considerable interest both experimentally [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16] and theoretically [17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41], because these setups are powerful platforms to simulate rich physics of stronglycorrelated materials [42, 43]. For the on-site repulsive interaction, a well-known second-order quantum phase transition between an antiferromagnetic Mott insulator and a metallic phase can emerge [45]. Another important breakthrough in recent experiments of ultracold Fermi atoms is to successfully create a synthetic spin-orbit coupling (SOC), with equal Rashba and Dresselhaus strengths, by a pair of counter-propagating Raman lasers [46, 47, 48, 49]. A second-order quantum phase transition between the spinrotating ferromagnetic Mott insulator and the SOC-induced metallic phase is predicted at the strong SOC.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
