Helical Majorana fermions in d+id'-wave topological superconductivity of doped correlated quantum spin Hall insulators

ORAL

Abstract

Large Hubbard $U$ limit of the Kane-Mele model on a zigzag ribbon of honeycomb lattice near half-filling is studied via a renormalized mean-field theory. The ground state exhibits time-reversal symmetry (TRS) breaking $d_{x^2-y^2} + {\it i}d_{xy}$-wave superconductivity. At large spin-orbit coupling, the $Z_2$ topological phase with non-trivial spin Chern number in the pure Kane-Mele model is persistent into the TRS broken state (called ``spin-Chern phase''), and has two pairs of counter-propagating helical Majorana modes at the edges. As the spin-orbit coupling is reduced, the system undergoes a topological quantum phase transition from the spin-Chern to chiral superconducting states. Possible relevance of our results to adatom-doped graphene and irridate compounds is discussed.Ref.:Shih-Jye Sun, Chung-Hou Chung, Yung-Yeh Chang, Wei-Feng Tsai, and Fu-Chun Zhang, arXiv:1506.02584.

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Authors

  • Chung-Hou Chung

    Electrophysics Department, National Chiao-Tung University, Taiwan, ROC, Chiao-Tung Univ and Natl Center for Theoretical Sciences, Taiwan, Dept. of Electrophysics, Natl. Chiao-Tung Univ., HsinChu, Taiwan, 300 ; Physics Division, Natl. Center for Theoretical Sciences, HsinChu, Taiwan, 300, National Chiao-Tung University, Taiwan

  • Shih-Jye Sun

    National University of Kaohsiung, Taiwan

  • Yung-Yeh Chang

    Department of Electrophysics, National Chiao-Tung University, HsinChu, Taiwan, 300, National Chiao-Tung University, Taiwan

  • Wei-Feng Tsai

    National Sun Yat-Sen University, Taiwan

  • Fuchun Zhang

    Department of Physics, Zhejiang University, Hangzhou 310027, China, Zhejiang Univ, Zejiang University, China