Enhanced electron dephasing in three-dimensional topological insulators

Abstract

Study of the dephasing in electronic systems is not only important for probing the nature of their ground states, but also crucial to harnessing the quantum coherence for information processing. In contrast to well-studied conventional metals and semiconductors, it remains unclear which mechanism is mainly responsible for electron dephasing in three-dimensional (3D) topological insulators (TIs). Here, we report on using weak antilocalization effect to measure the dephasing rates in highly tunable (Bi,Sb)${}_2$Te${}_3$ thin films. As the transport is varied from a bulk-conducting regime to surface-dominant transport, the dephasing rate is observed to evolve from a linear temperature dependence to a sublinear power-law dependence. While the former is consistent with the Nyquist electron-electron interactions commonly seen in ordinary 2D systems, the latter leads to enhanced electron dephasing at low temperatures and is attributed to the coupling between the surface states and the localized charge puddles in the bulk of 3D TIs.

18 pages, 4 figures, supplemental information available upon request or visit the ncomms website

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Cited by in corpus (5)

• Low temperature saturation of phase coherence length in topological insulators
• Observation of multichannel quantum coherent transport and electron-electron interaction in Bi2Te3 single crystal
• Phase transition and anomalous scaling in the quantum Hall transport of topological insulator Sn-Bi1.1Sb0.9Te2S devices
• Observation of long phase-coherence length in epitaxial La-doped CdO thin films
• Thickness dependence of electron-electron interactions in topological p-n junctions