Spin Fluctuations in Quantized Transport of Magnetic Topological Insulators

In magnetic topological insulators, quantized electronic transport is intertwined with spontaneous magnetic ordering, as magnetization controls band gaps, hence band topology, through the exchange interaction. We show that considering the exchange gaps at the mean-field level is inadequate to predict phase transitions between electronic states of distinct topology. Thermal spin fluctuations disturbing the magnetization can act as frozen disorders that strongly scatter electrons, reducing the onset temperature of quantized transport appreciably even in the absence of structural impurities. This effect, which has hitherto been overlooked, provides an alternative explanation of recent experiments on magnetic topological insulators.

Automated summary

In magnetic topological insulators, quantized electronic transport is affected by magnetic ordering and magnetization controlling band gaps, and thermal spin fluctuations can significantly reduce the onset temperature of quantized transport even without structural impurities. This overlooked effect provides an alternative explanation for recent experiments on magnetic topological insulators.