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Title: Topological superconducting phase in high-Tc superconductor MgB2 with Dirac–nodal-line fermions

Journal Article · · npj Computational Materials
ORCiD logo [1];  [1];  [2];  [3];  [3];  [4]
  1. Univ. of Utah, Salt Lake City, UT (United States)
  2. Univ. of Utah, Salt Lake City, UT (United States); Southern Univ. of Science and Technology, Shenzhen (China)
  3. Tsinghua Univ., Beijing (China)
  4. Univ. of Utah, Salt Lake City, UT (United States); Collaborative Innovation Center of Quantum Matter, Beijing (China)

Topological superconductors are an intriguing and elusive quantum phase, characterized by topologically protected gapless surface/edge states residing in a bulk superconducting gap, which hosts Majorana fermions. Unfortunately, all currently known topological superconductors have a very low transition temperature, limiting experimental measurements of Majorana fermions. With this work, we discover the existence of a topological Dirac–nodal-line state in a well-known conventional high-temperature superconductor, MgB2. First-principles calculations show that the Dirac–nodal-line structure exhibits a unique one-dimensional dispersive Dirac–nodal line, protected by both spatial-inversion and time-reversal symmetry, which connects the electron and hole Dirac states. Most importantly, we show that the topological superconducting phase can be realized with a conventional s-wave superconducting gap, evidenced by the topological edge mode of the MgB2 thin films showing chiral edge states. Our discovery may enable the experimental measurement of Majorana fermions at high temperature.

Research Organization:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE
Grant/Contract Number:
FG02-04ER46148
OSTI ID:
1619636
Alternate ID(s):
OSTI ID: 1527343
Journal Information:
npj Computational Materials, Vol. 5, Issue 1; ISSN 2057-3960
Publisher:
Nature Publishing GroupCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 51 works
Citation information provided by
Web of Science

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Cited By (7)

Robust topological nodal lines in halide carbides journal January 2019
Topological nodal line state in superconducting NaAlSi compound journal January 2019
Straight nodal lines and waterslide surface states observed in acoustic metacrystals journal July 2019
Observation of topological surface states in the high-temperature superconductor MgB 2 journal November 2019
Saddle-point Van Hove singularity and dual topological state in Pt 2 HgSe 3 journal December 2019
Phononic Weyl nodal straight lines in MgB 2 journal January 2020
Observation of topological surface states in the high-temperature superconductor MgB2 text January 2019

Figures / Tables (5)