Disorder-driven localization and electron interactions in BixTeI thin films

Strong disorder has a crucial effect on the electronic structure in quantum materials by increasing localization, interactions, and modifying the density of states. BixTeI films grown at room temperature and 230K exhibit dramatic magnetotransport effects due to disorder, localization, and electron correlation effects, including a metal-insulator transition at a composition that depends on growth temperature. The increased disorder caused by growth at 230 K causes the conductivity to decrease by several orders of magnitude for several compositions of BixTeI. The transition from metal to insulator with decreasing composition x is accompanied by a decrease in the dephasing length, which leads to the disappearance of the weak-antilocalization effect. Electron-electron interactions cause low temperature conductivity corrections on the metallic side and Efros-Shklovskii variable range hopping on the insulating side, effects which are absent in single crystalline BixTeI. The observation of a tunable metal-insulator transition and the associated strong localization and quantum effects in BixTeI shows the possibility of tuning spin transport in quantum materials via disorder.