Floquet second-order topological superconductor driven via ferromagnetic resonance

Abstract

We consider a Floquet triple-layer setup composed of a two-dimensional electron gas with spinorbit interactions, proximity coupled to an s-wave superconductor and to a ferromagnet driven at resonance. The ferromagnetic layer generates a time-oscillating Zeeman field which competes with the induced superconducting gap and leads to a topological phase transition. The resulting Floquet states support a second-order topological superconducting phase with a pair of localized zero-energy Floquet Majorana corner states. Moreover, the phase diagram comprises a Floquet helical topological superconductor, hosting a Kramers pair of Majorana edge modes protected by an effective time-reversal symmetry, as well as a gapless Floquet Weyl phase. The topological phases are stable against disorder and parameter variations and are within experimental reach.

Time-induced second-order topological superconductors

“…Before ending this section, it is necessary to compare this paper with relevant earlier literature on Floquet topological phases [47,[72][73][74][75][76][77][78][79][80][81]. First, Ref.…”

“…Second, some of Refs. [72][73][74][75][76][77][78][79][80][81] demonstrate the generation of higher-order topologically nontrivial phases by applying appropriate time-periodic drives to a static topologically trivial system. However, the latter may already possess the necessary requirements to host such higher-order topological phases on its own, such as accomplished by either tuning some system parameters or adding appropriate mass terms.…”

Floquet Second-Order Topological Phases in Momentum Space

“…In recent years, the study of HOTPs has been generalized to nonequilibrium systems, such as those subject to time-periodic drivings [ 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 ] or non-Hermitian effects [ 95 , 96 , 97 , 98 , 99 , 100 , 101 , 102 , 103 ]. The motivation behind the exploration of HOTPs in periodically driven systems is threefold.…”

“…Intriguing phenomena related to such momentum space topology including the quantized acceleration as an analog of the topological Thouless pump [ 107 ] and the integer quantum Hall effects from chaos [ 108 ]. The first two aspects have led to the discoveries of various Floquet HOTPs in both Hermitian and non-Hermitian systems [ 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 ]. However, the momentum-space counterpart of Floquet HOTPs and their topological characterizations have rarely been explored.…”

Floquet Engineering of Two Dimensional Photonic Waveguide Arrays with Cornered $π$ Mode

“…The topological feature of the corner modes have been enriched by introducing non-Hermitian terms into the Floquet systems [24,25]. One of the most interesting application of Floquet second order topological phase is to generated corner states in topological superconductor [26][27][28][29], so that the Floquet Majorana corner modes could be applied for quantum computing physics [30].…”