Multicriticality of two-dimensional class-D disordered topological superconductors

Majorana zero modes (MZMs) that obey the non-Abelian statistics have been intensively investigated for potential applications in topological quantum computing. The prevailing signals in tunneling experiments “fingerprinting” the existence of MZMs are the zero-energy bound states (ZEBSs). However, nearly all of the previously reported ZEBSs showing signatures of the MZMs are observed in difficult-to-fabricate heterostructures at very low temperatures and additionally require applied magnetic field. Here, by using in situ scanning tunneling spectroscopy, we detect the ZEBSs upon the interstitial Fe adatoms deposited on two different high-temperature superconducting one-unit-cell iron chalcogenides on SrTiO3(001). The spectroscopic results resemble the phenomenological characteristics of the MZMs inside the vortex cores of topological superconductors. Our experimental findings may extend the MZM explorations in connate topological superconductors toward an applicable temperature regime and down to the two-dimensional (2D) limit.

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Spin-polarized edge currents and Majorana fermions in one- and two-dimensional topological superconductors

Physical Review B ◽

10.1103/physrevb.92.214501 ◽

2015 ◽

Vol 92 (21) ◽

Cited By ~ 35

Author(s):

Kristofer Björnson ◽

Sergey S. Pershoguba ◽

Alexander V. Balatsky ◽

Annica M. Black-Schaffer

Keyword(s):

Majorana Fermions ◽

Two Dimensional ◽

Topological Superconductors ◽

Spin Polarized

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Platform of chiral Majorana edge modes and its quantum transport phenomena

Communications Physics ◽

10.1038/s42005-019-0250-5 ◽

2019 ◽

Vol 2 (1) ◽

Cited By ~ 1

Author(s):

James Jun He ◽

Tian Liang ◽

Yukio Tanaka ◽

Naoto Nagaosa

Keyword(s):

Quantum Transport ◽

Bound States ◽

Majorana Fermions ◽

Two Dimensional ◽

Quasi Particle ◽

One Dimensional ◽

Solid States ◽

Topological Superconductors ◽

Wide Range ◽

Majorana Modes

AbstractMajorana fermions, as electronic quasi-particle modes in solid states, have been under the focus of research due to their exotic physical properties. While the evidence of Majorana fermions as zero-dimensional bound states has been well established, the existence of one-dimensional Majorana modes is still under debate. The main reason is that the current theoretical proposals of platforms supporting such states are very challenging experimentally. Here, we propose a method to create two-dimensional topological superconductors with a heterostructure of ferromagnet, topological insulator thin film and superconductor. We show that such a system supports one-dimensional chiral Majorana edge modes in a wide range of parameters which is readily achievable in experiments. We further propose a new transport measurement to detect these modes.

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Polygon sign rules of Majorana fermions in two-dimensional topological superconductors

International Journal of Modern Physics B ◽

10.1142/s0217979216502131 ◽

2016 ◽

Vol 30 (27) ◽

pp. 1650213

Author(s):

Qiu-Bo Cheng ◽

Jing He ◽

Jing Yu ◽

Xiao-Ming Zhao ◽

Su-Peng Kou

Keyword(s):

Quantum Computation ◽

Numerical Approach ◽

Majorana Fermions ◽

Two Dimensional ◽

Line Defect ◽

Topological Superconductor ◽

Topological Superconductors ◽

Topological Quantum ◽

Different Types ◽

Topological Quantum Computation

Recently, Majorana fermions (MFs) have attracted intensive attention due to their exotic statistics and possible applications in topological quantum computation. They are proposed to exist in various two-dimensional (2D) topological systems, such as [Formula: see text] topological superconductor (SC) and nanowire–superconducting hybridization system. In this paper, we point out that Majorana fermions in different topological systems obey different types of polygon sign rules. A numerical approach is described to identify the type of polygon sign rule of the Majorana fermions. Applying the approach to study two 2D topological systems, we find that vortex-induced Majorana fermions obey topological polygon sign rule and line-defect-induced Majorana fermions obey normal polygon sign rule.

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Topological Edge States of a Majorana BBH Model

Condensed Matter ◽

10.3390/condmat6020015 ◽

2021 ◽

Vol 6 (2) ◽

pp. 15

Author(s):

Alfonso Maiellaro ◽

Roberta Citro

Keyword(s):

2D Materials ◽

Finite Size ◽

Majorana Fermions ◽

Topological Phase ◽

Two Dimensional ◽

Edge States ◽

Finite Size Scaling ◽

Topological Properties ◽

Berry Curvature ◽

Topological Superconductors

We investigate a Majorana Benalcazar–Bernevig–Hughes (BBH) model showing the emergence of topological corner states. The model, consisting of a two-dimensional Su–Schrieffer–Heeger (SSH) system of Majorana fermions with π flux, exhibits a non-trivial topological phase in the absence of Berry curvature, while the Berry connection leads to a non-trivial topology. Indeed, the system belongs to the class of second-order topological superconductors (HOTSC2), exhibiting corner Majorana states protected by C4 symmetry and reflection symmetries. By calculating the 2D Zak phase, we derive the topological phase diagram of the system and demonstrate the bulk-edge correspondence. Finally, we analyze the finite size scaling behavior of the topological properties. Our results can serve to design new 2D materials with non-zero Zak phase and robust edge states.

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