Volume 122, Number 2, April 2018
|Number of page(s)||5|
|Section||Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties|
|Published online||14 June 2018|
Extended Creutz ladder with spin-orbit coupling: A one-dimensional analog of the Kane-Mele model
1 Department of Physics, Bilkent University - TR-06800 Bilkent, Ankara, Turkey
2 MTA- BME Exotic Quantum Phases “Momentum” Research Group, Department of Physics, Budapest University of Technology and Economics - H-1111 Budapest, Hungary
Received: 3 April 2018
Accepted: 16 May 2018
We construct a topological one-dimensional ladder model following the steps which lead to the Kane-Mele model in two dimensions. Starting with a Creutz ladder we modify it so that the gap closure points can occur at either or . We then couple two such models, one for each spin channel, in such a way that time-reversal invariance is restored. We also add a Rashba spin-orbit coupling term. The model falls in the CII symmetry class. We derive the relevant topological index, calculate the phase diagram and demonstrate the existence of edge states. We also give the thermodynamic derivation (Středa-Widom) of the quantum spin Hall conductance. Approximate implementation of this result indicates that this quantity is sensitive to the topological behavior of the model.
PACS: 73.43.Cd – Theory and modeling / 73.43.Nq – Quantum phase transitions / 72.25.-b – Spin polarized transport
© EPLA, 2018
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