Predictions and Experiment in Topological 2D Superconductors
Phonon-induced transitions in topological superconductivity in proximitized double helical liquids
Author: Chen-Hsuan Hsu (Inst of Physics, Academia Sinica)
Helical liquids at the boundaries of time-reversal invariant two-dimensional topological insulators or three-dimensional second-order topological insulators exhibit interesting physical properties owing to the interplay of electronic correlations and spin-momentum locking. Upon inducing local and nonlocal pairings via the proximity effect, these helical liquids can host topological superconductivity with zero modes [1-3]. In this work, we investigate how phonons influence the helical liquids and the topological superconducting phase in proximitized systems [4]. Our nonperturbative analysis shows that electron-phonon coupling modifies the scaling dimensions of pairing operators, potentially leading to a singularity. Additionally, phonons enhance local pair formation over the nonlocal one, therefore inducing transitions between topological and trivial phases and resulting in the suppression of the associated topological zero modes. Given the ubiquitous presence of phonons, these results highlight potential challenges in maintaining stable topological zero modes in the helical channels.
Reference:
[1] Chen-Hsuan Hsu, Peter Stano, Jelena Klinovaja, and Daniel Loss, Semicond. Sci. Technol. 36, 123003 (2021), topical review.
[2] Jelena Klinovaja, Amir Yacoby, and Daniel Loss, Phys. Rev. B 90, 155447 (2014).
[3] Chen-Hsuan Hsu, Peter Stano, Jelena Klinovaja, and Daniel Loss, Phys. Rev. Lett. 121, 196801 (2018).
[4] Chen-Hsuan Hsu, Nanoscale Horiz. 9, 1725 (2024).