Topological Fulde-Ferrell superfluids in triangular lattices

Guo, Long-Fei; Li, Peng; Yi, Su

doi:10.1103/physreva.95.063610

Cited by 2 publications

(7 citation statements)

References 48 publications

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“…. Consistent with previous lattice studies [10,26,27], the Cooper pair momentum is in the y-direction, i.e. q = qy êy as the in-plane Zeeman field in the x-direction deforms the single-particle dispersions in the y-direction.…”

Section: Rashba-spin-orbit-coupled Fermions In a Square Latticesupporting

confidence: 87%

“…In spin-imbalanced systems without SOC, it has been shown, at the mean-field level, that in a square lattice the LO states should be slightly more energetically favorable than FF states [51], whereas in the presence of SOC both FF and LO states can exist as was shown in [10]. Moreover,in [20,26,27] the existence of topologically nontrivial FFLO phases in square and triangular lattices was predicted. However, studies presented in [10,20,26,27] did not consider the stability of FFLO phases against thermal phase fluctuations.In this work we investigate the stability of FF phases in lattice systems with and without SOC by calculating the BKT transition temperature T BKT .…”

mentioning

confidence: 86%

“…Moreover, in [20,26,27] the existence of topologically non-trivial FFLO phases in square and triangular lattices was predicted. However, studies presented in [10,20,26,27] did not consider the stability of FFLO phases against thermal phase fluctuations.…”

Section: Introductionmentioning

confidence: 98%

“…Moreover,in [20,26,27] the existence of topologically nontrivial FFLO phases in square and triangular lattices was predicted. However, studies presented in [10,20,26,27] did not consider the stability of FFLO phases against thermal phase fluctuations.In this work we investigate the stability of FF phases in lattice systems with and without SOC by calculating the BKT transition temperature T BKT . For a superconducting system the BKT temperature depends on the superfluid weight D s which is responsible for the dissipationless electric current and the Meissner effect-the fundamental properties of superconductors [52,53].…”

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confidence: 95%

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Superfluid weight and Berezinskii–Kosterlitz–Thouless temperature of spin-imbalanced and spin–orbit-coupled Fulde–Ferrell phases in lattice systems

2018

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We study the superfluid weight D s and Berezinskii-Kosterlitz-Thouless (BKT) transition temperatures T BKT in case of exotic Fulde-Ferrell (FF) superfluid states in lattice systems. We consider spinimbalanced systems with and without spin-orbit coupling (SOC) accompanied with in-plane Zeeman field. By applying mean-field theory, we derive general equations for D s and T BKT in the presence of SOC and the Zeeman fields for 2D Fermi-Hubbard lattice models, and apply our results to a 2D square lattice. We show that conventional spin-imbalanced FF states without SOC can be observed at finite temperatures and that FF phases are further stabilized against thermal fluctuations by introducing SOC. We also propose how topologically non-trivial SOC-induced FF phases could be identified experimentally by studying the total density profiles. Furthermore, the relative behavior of transverse and longitudinal superfluid weight components and the role of the geometric superfluid contribution are discussed.performed with quasi-one-dimensional population-imbalanced atomic gases have shown to be consistent with the existence of the FFLO state [33] but unambiguous proof is still missing.In addition to conventional spin-imbalanced quantum gas experiments, recently also synthetic SOC and Zeeman fields have been realized in ultracold gas experiments [34][35][36][37][38] which makes it possible to investigate SOC-induced FFLO states as well. As SOC-induced FFLO states have been predicted to be stable in larger parameter regime than conventional spin-imbalanced FFLO phases [10], synthetic SOC could provide a way to realize FFLO experimentally in ultracold gas systems [15].Low dimensionality has been predicted to favor 40]. However, in two and lower dimensional systems thermal phase fluctuations of the Cooper pair wave functions prevent the formation of true superfluid long range order as stated by the Mermin-Wagner theorem [41]. Instead, only quasi-long range order is possible. In two-dimensions, the phase transition from a normal Fermi gas to a superfluid state of quasi-long range order is determined by the Berezinskii-Kosterlitz-Thouless (BKT) transition temperature T BKT [42]. Below T BKT the system is a superfluid and above T BKT superfluidity is lost.In recent years, SOC-induced FFLO phases in two-dimensional systems have gained considerable attention [7,10,13,14,20,21,25]. In these systems it has been argued that SOC accompanied with the in-plane Zeeman field would yield FFLO states. Furthermore, in [13,14] it was predicted that in the presence of the out-of-plane Zeeman field, i.e. spin-imbalance, SOC-induced FFLO states could be topologically non-trivial and support Majorana fermions. Such topological FFLO states are conceptually new and exotic superconductive phases of matter. However, these studies were performed by applying mean-field theories which do not consider the stability of FFLO states against thermal phase fluctuations in terms of the BKT transition. Superfluidity and BKT transition temperatures of BCS phases in spin-...

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Section: Rashba-spin-orbit-coupled Fermions In a Square Latticesupporting

confidence: 87%

mentioning

confidence: 86%

Section: Introductionmentioning

confidence: 98%

mentioning

confidence: 95%

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Superfluid weight and Berezinskii–Kosterlitz–Thouless temperature of spin-imbalanced and spin–orbit-coupled Fulde–Ferrell phases in lattice systems

2018

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“…the Refs. [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. In this paper we discuss one such example, a strongly correlated quantum anomalous Hall (QAH) phase, called Chern Kondo (CK) * Corresponding author: xiongjunliu@pku.edu.cn insulator which was proposed recently in an optical lattice [49].…”

Section: Introductionmentioning

confidence: 99%

Magnetic effects on the Chern Kondo insulator

Niu

Liu

2018

Phys. Rev. B

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We examine the Chern Kondo insulator proposed in a square optical lattice with staggered flux induced by s-p orbital hybridization by revisiting its realization and taking into account the magnetic effects for the Kondo phases. The Ruderman-Kittel-Kasuya-Yoshida interaction is analyzed at the weak s-p hybridization regime, with the anisotropic magnetic effects being discussed. Furthermore, the paramagnetic and magnetic phases coexisting with Kondo couplings are systematically investigated through the slave-boson theory, for which the rich phases are obtained, including the antiferromagnetic, collinear antiferromagnetic Kondo insulator, and Kondo metal phases. The magnetic orders are shown to enhance the effective Kondo hybridization compared with the case without taking into account magnetic effects, and exhibit different influences on the bulk topology. In particular, the antiferromagnetic ordering always enhances the topological phase by increasing bulk gap of the Chern Kondo phases. The results show the rich topological and magnetic effects obtained in the present Chern Kondo lattice model. We also investigate how to identify the topology and strong correlation effects through measuring the Hall conductance and double occupancy, which are achievable in ultracold atom experiments. arXiv:1805.01383v4 [cond-mat.str-el]

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Topological Fulde-Ferrell superfluids in triangular lattices

Cited by 2 publications

References 48 publications

Superfluid weight and Berezinskii–Kosterlitz–Thouless temperature of spin-imbalanced and spin–orbit-coupled Fulde–Ferrell phases in lattice systems

Superfluid weight and Berezinskii–Kosterlitz–Thouless temperature of spin-imbalanced and spin–orbit-coupled Fulde–Ferrell phases in lattice systems

Magnetic effects on the Chern Kondo insulator

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