Hikami-Larkin-Nagaoka (HLN) treatment of the Magneto Conductivity of Bi2Te3 Topological Insulator

TL;DR

This study analyzes the magneto-conductivity of Bi2Te3 topological insulator crystals using the HLN model, revealing the coexistence of surface and bulk conduction mechanisms and how they vary with temperature.

Contribution

It demonstrates the application of the HLN equation to Bi2Te3, quantifying surface and bulk contributions and their temperature dependence, which was not previously detailed.

Findings

Conduction involves both surface WAL and bulk WL states.

HLN coefficient ranges from -0.86 to -1.5 depending on temperature.

Phase coherence length decreases with increasing temperature.

Abstract

We report the magneto-conductivity analysis at different temperatures under magnetic field of up to 5Tesla of a well characterized Bi2Te3 crystal. Details of crystal growth and various physical properties including high linear magneto resistance are already reported by some of us. To elaborate upon the transport properties of Bi2Te3 crystal, the magneto conductivity is fitted to the known HLN (Hikami Larkin Nagaoka) equation and it is found that the conduction mechanism is dominated by both surface driven WAL (weak anti localization) and the bulk WL states. The value of HLN equation coefficient signifying the type of localization (WL, WAL or both WL and WAL) falls within the range of -0.5 to -1.5. In our case, the low field (0.25Tesla) fitting of studied crystal exhibited value close to -0.86 for studied temperatures of up to 50K, indicating both WAL and WL contributions. The phase coherence length is found to decrease from 98.266 to 40.314nm with increasing temperature. Summarily, the short letter reports the fact that bulk Bi2Te3 follows the HLN equation and quantitative analysis of the same facilitates to know the quality of studied crystal in terms of WAL to WL contributions and thus the surface to bulk conduction ratio.