Edge states, entanglement entropy spectra and critical hopping couplings of anisotropic honeycomb lattices

Author： Chung Ming-Chiang Jhu Yi-Hao Chen Pochung Yip Sungkit

E-ISSN： 1286-4854|95|2|27003-27003

ISSN： 0295-5075

Source： EPL (EUROPHYSICS LETTERS), Vol.95, Iss.2, 2011-06, pp. : 27003-27003

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

For bipartite honeycomb lattices, we show that the Berry phase depends not only on the shape of the system but also on the hopping couplings. Using the entanglement entropy spectra obtained by diagonalizing the block Green's function matrices, the maximally entangled states with the eigenvalue λ_m=1/2 of the reduced density matrix are shown to have one-to-one correspondences to the zero-energy states of the lattice with open boundaries. The existence of these states depends on the Berry phase. For systems with finite bearded edges along thex-direction, we show that new maximally entangled states (zero-energy states) appear pair-by-pair when one increases the hopping coupling h over the critical values h_c's.