Impurities and defects are ubiquitous in topological insulators (TIs) andthus understanding the effects of disorder on electronic transport isimportant. We calculate the conductance distributions of disordered 2D TI wiresmodeled by the Bernevig-Hughes-Zhang (BHZ) Hamiltonian with realisticparameters, and show that disorder drives the TIs into different quantumphases. We perform a statistical analysis of the conductance fluctuations inall quantum phases and find that although the BHZ Hamiltonian belongs to thesymplectic symmetry class ($\beta=4$), the conductance fluctuations follow thestatistics of unitary universality class $\beta=2$. Strong disorder, however,would drive the conductance fluctuations to universality class $\beta=1$. Atthe phase transitions, the conductance distributions change drastically fromone quantum phase to another due to the different degrees of localization ofthe helical edge and bulk states.
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