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Title: Observation of the anisotropic Dirac cone in the band dispersion of 112-structured iron-based superconductor Ca{sub 0.9}La{sub 0.1}FeAs{sub 2}

Abstract

CaFeAs{sub 2} is a parent compound of recently discovered 112-type iron-based superconductors. It is predicted to be a staggered intercalation compound that naturally integrates both quantum spin Hall insulating and superconducting layers and an ideal system for the realization of Majorana modes. We performed a systematical angle-resolved photoemission spectroscopy and first-principles calculation study of the slightly electron-doped CaFeAs{sub 2}. We found that the zigzag As chain of 112-type iron-based superconductors play a considerable role in the low-energy electronic structure, resulting in the characteristic Dirac-cone like band dispersion as the prediction. Our experimental results further confirm that these Dirac cones only exist around the X but not Y points in the Brillouin zone, breaking the S{sub 4} symmetry at iron sites. Our findings present the compelling support to the theoretical prediction that the 112-type iron-based superconductors might host the topological nontrivial edge states. The slightly electron doped CaFeAs{sub 2} would provide us a unique opportunity to realize and explore Majorana fermion physics.

Authors:
; ; ; ; ;  [1]; ; ; ;  [2];  [1];  [3];  [1];  [3];  [3];  [1];  [3];  [4]
  1. State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, Shanghai 200050 (China)
  2. Department of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189 (China)
  3. (China)
  4. (CENSE), Shanghai 200050 (China)
Publication Date:
OSTI Identifier:
22594378
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 109; Journal Issue: 4; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANISOTROPY; BRILLOUIN ZONES; CONES; DISPERSIONS; DOPED MATERIALS; ELECTRONIC STRUCTURE; ELECTRONS; IRON; LAYERS; MAJORANA FERMIONS; MAJORANA SPINORS; PHOTOELECTRON SPECTROSCOPY; PHOTOEMISSION; SPIN; SUPERCONDUCTORS; SYMMETRY; TOPOLOGY

Citation Formats

Liu, Z. T., Li, M. Y., Fan, C. C., Yang, H. F., Liu, J. S., Wang, Z., Xing, X. Z., Zhou, W., Sun, Y., Shi, Z. X., Yao, Q., State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, Li, W., State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, CAS-Shanghai Science Research Center, Shanghai 201203, Shen, D. W., E-mail: dwshen@mail.sim.ac.cn, CAS-Shanghai Science Research Center, Shanghai 201203, and CAS Center for Excellence in Superconducting Electronics. Observation of the anisotropic Dirac cone in the band dispersion of 112-structured iron-based superconductor Ca{sub 0.9}La{sub 0.1}FeAs{sub 2}. United States: N. p., 2016. Web. doi:10.1063/1.4960164.
Liu, Z. T., Li, M. Y., Fan, C. C., Yang, H. F., Liu, J. S., Wang, Z., Xing, X. Z., Zhou, W., Sun, Y., Shi, Z. X., Yao, Q., State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, Li, W., State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, CAS-Shanghai Science Research Center, Shanghai 201203, Shen, D. W., E-mail: dwshen@mail.sim.ac.cn, CAS-Shanghai Science Research Center, Shanghai 201203, & CAS Center for Excellence in Superconducting Electronics. Observation of the anisotropic Dirac cone in the band dispersion of 112-structured iron-based superconductor Ca{sub 0.9}La{sub 0.1}FeAs{sub 2}. United States. doi:10.1063/1.4960164.
Liu, Z. T., Li, M. Y., Fan, C. C., Yang, H. F., Liu, J. S., Wang, Z., Xing, X. Z., Zhou, W., Sun, Y., Shi, Z. X., Yao, Q., State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, Li, W., State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, CAS-Shanghai Science Research Center, Shanghai 201203, Shen, D. W., E-mail: dwshen@mail.sim.ac.cn, CAS-Shanghai Science Research Center, Shanghai 201203, and CAS Center for Excellence in Superconducting Electronics. Mon . "Observation of the anisotropic Dirac cone in the band dispersion of 112-structured iron-based superconductor Ca{sub 0.9}La{sub 0.1}FeAs{sub 2}". United States. doi:10.1063/1.4960164.
@article{osti_22594378,
title = {Observation of the anisotropic Dirac cone in the band dispersion of 112-structured iron-based superconductor Ca{sub 0.9}La{sub 0.1}FeAs{sub 2}},
author = {Liu, Z. T. and Li, M. Y. and Fan, C. C. and Yang, H. F. and Liu, J. S. and Wang, Z. and Xing, X. Z. and Zhou, W. and Sun, Y. and Shi, Z. X. and Yao, Q. and State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433 and Li, W. and State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433 and CAS-Shanghai Science Research Center, Shanghai 201203 and Shen, D. W., E-mail: dwshen@mail.sim.ac.cn and CAS-Shanghai Science Research Center, Shanghai 201203 and CAS Center for Excellence in Superconducting Electronics},
abstractNote = {CaFeAs{sub 2} is a parent compound of recently discovered 112-type iron-based superconductors. It is predicted to be a staggered intercalation compound that naturally integrates both quantum spin Hall insulating and superconducting layers and an ideal system for the realization of Majorana modes. We performed a systematical angle-resolved photoemission spectroscopy and first-principles calculation study of the slightly electron-doped CaFeAs{sub 2}. We found that the zigzag As chain of 112-type iron-based superconductors play a considerable role in the low-energy electronic structure, resulting in the characteristic Dirac-cone like band dispersion as the prediction. Our experimental results further confirm that these Dirac cones only exist around the X but not Y points in the Brillouin zone, breaking the S{sub 4} symmetry at iron sites. Our findings present the compelling support to the theoretical prediction that the 112-type iron-based superconductors might host the topological nontrivial edge states. The slightly electron doped CaFeAs{sub 2} would provide us a unique opportunity to realize and explore Majorana fermion physics.},
doi = {10.1063/1.4960164},
journal = {Applied Physics Letters},
number = 4,
volume = 109,
place = {United States},
year = {Mon Jul 25 00:00:00 EDT 2016},
month = {Mon Jul 25 00:00:00 EDT 2016}
}