Weak antilocalization and conductance fluctuation in a submicrometer-sized wire of epitaxial Bi ₂Se ₃

In this paper, we address the phase-coherent transport in a submicrometer-sized Hall bar made of epitaxial Bi ₂Se ₃ thin film by probing the weak antilocalization (WAL) and the magnetoresistance fluctuation below 22 K. The WAL effect is well described by the Hikami-Larkin-Nagaoka model, where the temperature dependence of the coherence length indicates that electron conduction occurs quasi-one-dimensionally in the narrow Hall bar. The temperature-dependent magnetoresistance fluctuation is analyzed in terms of the universal conductance fluctuation, which gives a coherence length consistent with that derived from the WAL effect.