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Non-Centrosymmetric Superconductors on Honeycomb Lattice

Research Highlight
Poster:Daw-Wei WangPost date:2018-09-13
Non-Centrosymmetric Superconductors on Honeycomb L
Non‐centrosymmetric supercondutors (NCSs), long being discovered in heavy fermion systems, give rise to an exotic mixture of even‐parity spin‐singlet and odd‐parity triplet Cooper pairing due to their lack of spatial inversion symmetry. Der‐Hau Lee and Chung‐Hou Chung (Professor of NCTU and Coordinator of TG8, NCTS) theoretically investigate the topological nature of possible NCSs in much more tunable graphene‐based materials on the two‐dimensional honeycomb structure with both intrinsic and Rashba spin‐orbit couplings. The generic topologically non‐trivial superconducting phase diagram of the model system is explored. Over a certain parameter range, the authors find the existence of paritymixing superconducting state with co‐existing spin‐singlet d+id and spin‐triplet p+ip wave pairing. On a zigzag nanoribbon, the parity‐mixing superconducting state shows co‐existing counter‐propagating helical and co‐propagating chiral Majorana fermions at edges as a result of non‐trivial topological property. These results are applicable for transition metal dichalcogenides (TMDs), which show promising properties in valleytronics and spintronics applications.

Their work was sulected as Editor's Choices and Journal Cover of Phys. Status Solidi B.

Reference: Phys. Status Solidi B 2018, 255, 1800114 (2018)
https://onlinelibrary.wiley.com/doi/pdf/10.1002/pssb.201800114

PS: Figure caption for the cover picture:

Left: 3D bulk band dispersion in the d+id singlet- p+ip triplet mixing superconducting state of the model 

on a 2D honeycomb lattice; Top right: Dispersion of low energy excitation of the parity-mixing superconducting state 

on a finite-sized zigzag ribbon of 2D honeycomb lattice; Bottom right: Majorana fermion (MF) modes (indicated by points A,B,C,D,E, and F shown Top right) appear at edges of the zigzag ribbon as non-trivial topological edge states of the model on honeycomb lattice. They consist of one co-propagating chiral MF (C,D with red arrows) and a pair of counter-propagating helical MFs (A,B and E,F with blue arrows).

 
Last modification time:2018-09-13 PM 12:58

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