Hopping conduction in strongly insulating states of a diffusive bent quantum Hall junction

Transport studies of a bent quantum Hall junction at integer filling factor $\ensuremath{\nu}$ show strongly insulating states $(\ensuremath{\nu}=1,2)$ at higher fields. In this paper we analyze the strongly insulating behavior as a function of temperature $T$ and dc bias ${V}_{\text{dc}}$ in order to classify the localization mechanisms responsible for the insulating state. The temperature dependence suggests a crossover from activated nearest-neighbor hopping at higher $T$ to variable-range hopping conduction $G\ensuremath{\sim}\text{exp}[\ensuremath{-}{(\frac{{T}_{0}}{T})}^{1/2}]$ at lower $T$. The base temperature electric-field dependence shows $I(\mathcal{E})\ensuremath{\sim}\text{exp}[\ensuremath{-}{(\frac{{\mathcal{E}}_{0}}{\mathcal{E}})}^{1/2}]$, consistent with one-dimensional (1D) variable-range hopping conduction. We observe almost identical behavior at $\ensuremath{\nu}=1$ and $\ensuremath{\nu}=2$, and discuss how the bent quantum Hall junction conductance appears to be independent of the bulk spin state. Various models of 1D variable-range hopping, which either include or ignore interactions are compared all of which are consistent with the basic model of disorder coupled counterpropagating quantum Hall edges.