J. Phys. Soc. Jpn. 74, pp. 1674-1677 (2005) [4 Pages]
LETTERS

Chern Numbers in Discretized Brillouin Zone: Efficient Method of Computing (Spin) Hall Conductances

+ Affiliations
1Department of Mathematical Sciences, Ibaraki University, Mito 310-85122Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-86563Institute of Applied Beam Science, Ibaraki University, Mito 310-8512

We present a manifestly gauge-invariant description of Chern numbers associated with the Berry connection defined on a discretized Brillouin zone. It provides an efficient method of computing (spin) Hall conductances without specifying gauge-fixing conditions. We demonstrate that it correctly reproduces quantized Hall conductances even on a coarsely discretized Brillouin zone. A gauge-dependent integer-valued field, which plays a key role in the formulation, is evaluated in several gauges. An extension to the non-Abelian Berry connection is also given.

©2005 The Physical Society of Japan

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