Lattice distortion induced first- and second-order topological phase transition in a rectangular high-Tc superconducting monolayer

Abstract

We theoretically study the lattice distortion induced first- and second-order topological phase transition in rectangular FeSexTe1−x monolayer. When compressing the lattice constant in one direction, our first-principles calculation shows that the FeSexTe1−x undergoes a band inversion at Γ point in a wide doping range, say x∈(0.0,0.7), which indicates the first-order topological phase transition of its electronic band structure. Meanwhile, because the unidirectional pressure breaks C4 symmetry, the topological edge states along the (100) and (010) directions have different Dirac energy. Given the high-temperature superconductivity of FeSexTe1−x monolayer, we found that the C4 symmetry breaking is essential to support Majorana corner states in either presence or absence of time-reversal symmetry. Especially in the case of breaking time-reversal symmetry, we can obtain a single Majorana zero mode at each corner without concerning the details of the superconducting pairing symmetries and applied Zeeman form, which can potentially bring advantages in the experimental implementation.

Source-reported materials — not catalogue approval

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