Large positive magneto-conductivity at microwave frequencies in the compensated topological insulator BiSbTeSe2

Abstract

The bulk electronic properties of compensated topological insulators are strongly affected by the self-organized formation of charge puddles at low temperature, but their response in the microwave frequency range is little studied. We employed broadband impedance spectroscopy up to 5 GHz to address the ac transport properties of well-compensated BiSbTeSe2, where charge puddles are known to form as metallic entities embedded in an insulating host. It turns out that the average puddle size sets the characteristic frequency cut-off in the GHz range, across which the insulating dc behavior is separated from a metal-like high-frequency response of delocalized carriers within the puddles. The cut-off frequency is found to be controlled by a magnetic field, giving rise to a large positive magneto-conductivity observable only in the GHz range. This curious phenomenon is driven by the Zeeman energy which affects the local band filling in the disordered potential landscape to enhance the puddle size.

References in corpus (4)

• Observation of Dirac Holes and Electrons in a Topological Insulator
• Why is the bulk resistivity of topological insulators so small?
• Charge puddles in the bulk and on the surface of the topological insulator BiSbTeSe${}_2$ studied by scanning tunneling microscopy and optical spectroscopy
• Charge puddles in a completely compensated topological insulator

Cited by in corpus (2)

• Phonon thermal Hall effect in charge-compensated topological insulators
• Propagation, dissipation and breakdown in quantum anomalous Hall edge states probed by microwave edge plasmons