Gapless topological Fulde-Ferrell superfluidity induced by in-plane Zeeman field

Abstract

Topological superfluids are recently discovered quantum matters that host topologically protected gapless edge states known as Majorana fermions - exotic quantum particles that act as their own anti-particles and obey non-Abelian statistics. Their realizations are believed to lie at the heart of future technologies such as fault-tolerant quantum computation. To date, the most efficient scheme to create topological superfluids and Majorana fermions is based on the Sau-Lutchyn-Tewari-Das Sarma model with a Rashba-type spin-orbit coupling on the }\textbf{\textit{x-y}}\textbf{ plane and a large out-of-plane (perpendicular) Zeeman field along the }\textbf{\textit{z}}\textbf{-direction. Here we propose an alternative setup, where the topological superfluid phase is driven by applying an in-plane Zeeman field. This scheme offers a number of new features, notably Cooper pairings at finite centre-of-mass momentum (i.e., Fulde-Ferrell pairing) and gapless excitations in the bulk. As a result, a novel gapless topological quantum matter with inhomogeneous pairing order parameter appears. It features unidirected Majorana surface states at boundaries, which propagate in the same direction and connect two Weyl nodes in the bulk. We demonstrate the emergence of such an exotic topological matter and the associated Majorana fermions in spin-orbit coupled atomic Fermi gases and determine its parameter space. The implementation of our scheme in semiconductor/superconductor heterostructures is briefly discussed.

8 pages, 5 figures

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Cited by in corpus (13)

• Type-II Weyl Points in Three-Dimensional Cold Atom Optical Lattices
• Dynamical topological phases in quenched spin-orbit coupled degenerate Fermi gas
• Berezinskii-Kosterlitz-Thouless Phase Transition in 2D Spin-Orbit Coupled Fulde-Ferrell Superfluids
• Pairing Superfluidity in Spin-Orbit Coupled Ultracold Fermi Gases
• Topological Fulde-Ferrell Superfluids of a Spin-Orbit Coupled Fermi Gas
• Superfluid density and Berezinskii-Kosterlitz-Thouless transition of a spin-orbit coupled Fulde-Ferrell superfluid
• Large Chern Number Topological Superfluids in Coupled Layer System
• Three-dimensional spin-orbit coupled Fermi gases: Fulde-Ferrell pairing, Majorana fermions, Weyl fermions and gapless topological superfluidity
• Larkin-Ovchinnikov state of superconducting Weyl metals: Fundamental differences between pairings restricted and extended in the $\text{k}$-space
• Spin-imbalanced ultracold Fermi gases in a two-dimensional array of tubes
• Exotic Topological States with Raman-Induced Spin-Orbit Coupling
• Two-dimensional helical superconductivity and gapless superconducting edge modes in the 1T${}^{\prime }$-WS${}_2$/2H-WS${}_2$ heterophase bilayer
• Nodal Line Topological Superfluid and Multiply Protected Majorana Fermi Arc in a Three-Dimensional Time-Reversal-Invariant Superfluid Model