Nematic orders and nematicity-driven topological phase transition in FeSe

Wu, Xianxin; Liang, Yi; Fan, Heng; Hu, Jiangping

doi:10.48550/arxiv.1603.02055

Cited by 11 publications

(17 citation statements)

References 23 publications

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“…Topological band inversion was predict in multiple compounds, such as FeSe/STO monolayer [85], Fe(Te,Se) monolayer [86], Fe(Te,Se) single crystals [87], CaFeAs 2 [88], and etc. Theories also predicted the appearance of topological band structure owing to electronic orders [89][90][91][92][93][94][95][96][97]. For example, the evidence of topological bands has been found in the SDW state of BaFe 2 As 2 [89][90][91][92] and the nematic state of FeSe single crystals [94][95][96][97].…”

Section: (D))mentioning

confidence: 96%

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Emergent vortex Majorana zero mode in iron-based superconductors

Kong¹,

Ding²

2020

Acta Phys. Sin.

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The vortex of iron-based superconductors is emerging as a promising platform for Majorana zero mode, owing to a magic integration among intrinsic vortex winding, non-trivial band topology, strong electron-electron correlations, high-Tc superconductivity and the simplification of single material. It overcomes many difficulties suffered in heterostructure-based Majorana platforms, including small topological gap, interfacial contamination, lattice imperfections, and etc. Isolated zero-bias peaks have been found in vortex of several iron-based superconductors. So far, studies from both experimental and theoretical aspects strongly indicate the realization of vortex Majorana zero mode, with a potential to be applied to fault-tolerant quantum computation. By taking Fe(Te,Se) superconductor as an example, here we review the original idea and research progress of Majorana zero modes in this new platform. After introducing the identifications of topological band structure and real zero modes in vortex, we summarize the physics behaviors of vortex Majorana zero modes systematically. First, relying on the behavior of the zero mode wave function and evidence of quasiparticle poisoning, we analyze the mechanism of emergence of vortex Majorana zero modes. Secondly, assisted with some well-established theories, we elaborate the measurements on "Majorana symmetry" and topological nature of vortex Majorana zero modes. After that, we switch from quantum physics to quantum engineering, and analyze the performance of vortex Majorana zero modes under real circumstances, which may potentially benefit the exploration of practical applications in the future. This review follows the physics properties of vortex Majorana zero modes, especially emphasizes the link between phenomena and mechanisms. It provides a chance to bridge the gap between the well-established theories and the newly discovered "iron home" of Majoranas.

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Section: (D))mentioning

confidence: 96%

“…Theories also predicted the appearance of topological band structure owing to electronic orders [89][90][91][92][93][94][95][96][97]. For example, the evidence of topological bands has been found in the SDW state of BaFe 2 As 2 [89][90][91][92] and the nematic state of FeSe single crystals [94][95][96][97].…”

Section: (D))mentioning

confidence: 96%

Emergent vortex Majorana zero mode in iron-based superconductors

Kong¹,

Ding²

2020

Acta Phys. Sin.

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“…Thus, if the iron chalcogenides are in the signchanged s-wave states, we can expect that they are secondorder topological superconductors and must exhibit two Dirac cones on the (10)/(01) boundary and one Majorana Kramers' pair at the intersection between the ( 11) and ( 11) edges. To demonstrate this, we carry out our calculation in a five-orbital model which describes the genuine band structures of ironbased superconductors 96 . The result is given in the SM, which confirms that iron chalcogenides, if they host the sign changed s-wave states between two electron pockets, are second-order topological superconductors.…”

Section: (B) a S-wave (A 1g ) Superconductivity Is Described Generall...mentioning

confidence: 99%

“…For the tight-binding part, we adopt the Hamiltonian in Ref. 96 in which all five d orbitals of the Fe atoms are taken into account, and utilize the parameters in Table .I to fit the band structures of a single layer FeSe shown in Fig. 6(a).…”

Section: Calculations For the Iron-selenide Superconductorsmentioning

confidence: 99%

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Topological Superconductivity in an s-wave Superconductor and Its Implication to Iron-based Superconductors

Qin,

Fang,

Zhang

et al. 2021

Preprint

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In the presence of both space and time reversal symmetries, an s-wave A 1g superconducting state is usually topologically trivial. Here we demonstrate that an exception can take place in a type of nonsymmorphic lattice structures. We specify the demonstration in a system with a centrosymmetric space group P4/nmm, the symmetry that governs iron-based superconductors, by showing the existence of a second-order topological state protected by a mirror symmetry. The topological superconductivity is featured by 2Z degenerate Dirac cones on the (10) edge, and Z pairs of Majorana modes at the intersection between the ( 11) and ( 11) edges. The topological invariance and Fermi surface criterion for the topological state are provided. Moreover, we point out that the previously proposed s-wave state in iron-based superconductors, which features a sign-changed superconducting order parameter between two electron pockets, is such a topological state. Thus, these results not only open a new route to pursue topological superconductivity, but also establish a measurable quantity to settle one long-lasting debate on the pairing nature of iron-based superconductors.

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Topological vortex phase transitions in iron-based superconductors

Qin

et al. 2019

Science Bulletin

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We study topological vortex phases in iron-based superconductors. Besides the previously known vortex end Majorana zero modes (MZMs) phase stemming from the existence of a three dimensional (3D) strong topological insulator state, we show that there is another topologically nontrivial phase as iron-based superconductors can be doped superconducting 3D weak topological insulators (WTIs). The vortex bound states in a superconducting 3D WTI exhibit two different types of quantum states, a robust nodal superconducting phase with pairs of bulk MZMs and a full-gap topologically nontrivial superconducting phase which has single vortex end MZM in a certain range of doping level. Moreover, we predict and summarize various topological phases in iron-based superconductors, and find that carrier doping and interlayer coupling can drive systems to have phase transitions between these different topological phases. PACS numbers: 74.70.-b, 74.25.Ha, 74.20.Pq arXiv:1901.03120v1 [cond-mat.supr-con]

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Nematic orders and nematicity-driven topological phase transition in FeSe

Cited by 11 publications

References 23 publications

Emergent vortex Majorana zero mode in iron-based superconductors

Emergent vortex Majorana zero mode in iron-based superconductors

Topological Superconductivity in an s-wave Superconductor and Its Implication to Iron-based Superconductors

Topological vortex phase transitions in iron-based superconductors

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