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Quantum revivals in HgTe/CdTe quantum wells and topological phase transitions
by A. Mayorgas, M. Calixto, N. A. Cordero, E. Romera, O. Castaños
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Submission summary
| Authors (as registered SciPost users): | Alberto Mayorgas |
| Submission information | |
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| Preprint Link: | https://arxiv.org/abs/2401.03884v1 (pdf) |
| Date submitted: | 2024-01-09 14:45 |
| Submitted by: | Mayorgas, Alberto |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approaches: | Theoretical, Computational |
Abstract
The time evolution of a wave packet is a tool to detect topological phase transitions in two-dimensional Dirac materials, such as graphene and silicene. Here we extend the analysis to HgTe/CdTe quantum wells and study the evolution of their electron current wave packet, using 2D effective Dirac Hamiltonians and different layer thicknesses. We show that the two different periodicities that appear in this temporal evolution reach a minimum near the critical thickness, where the system goes from normal to inverted regime. Moreover, the maximum of the electron current amplitude changes with the layer thickness, identifying that current maxima reach their higher value at the critical thickness. Thus, we can characterize the topological phase transitions in terms of the periodicity and amplitude of the electron currents.
Current status:
Reports on this Submission
Report #1 by Anonymous (Referee 1) on 2024-4-1 (Invited Report)
- Cite as: Anonymous, Report on arXiv:2401.03884v1, delivered 2024-04-01, doi: 10.21468/SciPost.Report.8804
Strengths
Innovative approach to detect topological phase transitions, applied to a material of experimental relevance.
Weaknesses
The model Hamiltonian is somewhat oversimplified.
Report
This work is a follow-up of Ref. 7, where the authors develop the general theory. Here the focus is on an application to a particular material, which is interesting and worth publishing, but lacks the "breakthrough" character required for SciPost Physics. It seems more appropriate for SciPost Physics Core.
One issue would be worth considering: the model Hamiltonian which the authors study does not couple the spin blocks, see Eq. 1. It is known that spin-orbit interaction without inversion symmetry introduces a coupling of the spin blocks. Even if the quantum well is symmetric, there remains a bulk inversion asymmetry. How would a coupling term affect the results?
Requested changes
Assess the effect of coupling of the spin blocks, at least qualitatively, if possible, quantitatively.
Author: Alberto Mayorgas on 2024-04-19 [id 4434]
(in reply to Report 1 on 2024-04-01)Dear Referees,
Following the referee suggestions, we have added a new section V to study the effect of spin-orbit interaction without inversion symmetry introducing a constant coupling of the spin blocks. We focused on the effect of spin-orbit interaction on classical and revival times. We have seen that the spin coupling has hardly any effect on classical and revival times near the critical thickness where the topological phase transition takes place. Revival times turn to be more sensitive than classical times to the coupling away from the critical point. Both, classical and revival, times remain minimal at the critical point. More details (with new figures) can be found in the new version of the manuscript.
We hope that the changes introduced in the manuscript will make it suitable for publication by SciPost Physics Core.
Sincerely,
The authors