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arXiv · 1103.1226

Z$_2$ topological number of local quantum clusters in the orthogonal dimer model

Isao Maruyama·Sho Tanaya·Mitsuhiro Arikawa·Yasuhiro Hatsugai
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Abstract

We have studied the $Z_2$ topological number defined by the Berry phase for the gapped frustrated systems including the orthogonal dimer model which has a direct product state of local quantum clusters as the exact ground state. The $Z_2$ topological number can clarify what kind of the local quantum clusters is formed to lift the macroscopic degeneracy due to frustration, even when the exact ground state is unknown. As a demonstration, the dimer-singlet and plaquette-singlet phase are identified by two kinds of Z$_2$ topological numbers in the Shastry-Sutherland model and its generalization realized experimentally as SrCu$_2$(BO$_3$)$_2$ and CaV$_4$O$_9$.

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Isao Maruyama, Sho Tanaya, Mitsuhiro Arikawa, Yasuhiro Hatsugai. 2011-03-07. Z$_2$ topological number of local quantum clusters in the orthogonal dimer model. https://doi.org/10.1088/1742-6596%2F320%2F1%2F012019

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