Study of phase decoherence in GeSn (8%) through measurements of the weak antilocalization effect
Date
2024-11-18
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Applied Physics
Abstract
Alloying germanium with tin offers a means to modulate germanium’s electronic structure, enabling a greater degree of control over quantum properties such as the retention of the phase or spin of the electron wave. However, the extent to which the presence of high dopant concentrations in GeSn alters these quantum behaviors is poorly understood. Here, we investigate the role of dopant concentrations on phase coherence through measurements of the weak antilocalization (WAL) effect at temperatures between 30 mK and 10 K in p-GeSn (8%) thin films, which were doped to a series of carrier densities on the order of 1012 cm 2. Phase coherence and spin–orbit lengths were extracted from the magnetoconductivities using the 2D Hikami–Larkin–Nagaoka model. Phase coherence lengths peaked at 577, 593, and 737 nm for the low-, mid-, and high-density samples, while upper limits on the spin–orbit lengths of less than 25 nm were relatively independent of carrier density and temperature. The phase coherence lengths increased as the temperature decreased but changed only minimally with carrier density, contrary to common models of temperature-dependent inelastic scattering. Saturation of the phase coherence lengths occurred below 600 mK. Based on these findings, intrinsically generated inelastic scattering mechanisms such as two-level systems or impurity band scattering likely contribute to phase decoherence in these alloys. Our results provide insight into the inelastic scattering mechanisms of GeSn, while suggesting a need for further investigation into phase decoherence mechanisms in doped group-IV alloys.
Description
This article was originally published in Journal of Applied Physics. The version of record is available at: https://doi.org/10.1063/5.0233728.
© 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). https://doi.org/10.1063/5.0233728
Keywords
doping, electronic transport, quantum effects, electric measurements, alloys, thin films, spin-orbit interactions, inelastic scattering
Citation
Bradicich, Adelaide, Priyanka Petluru, Shiva Davari, Haochen Zhao, Siddhant Gangwal, Chia-You Liu, Dragica Vasileska, et al. “Study of Phase Decoherence in GeSn (8%) through Measurements of the Weak Antilocalization Effect.” Journal of Applied Physics 136, no. 21 (December 7, 2024): 214301. https://doi.org/10.1063/5.0233728.