| Full text | |
| Author(s): |
Califrer, Igor J.
;
Penteado, Poliana H.
;
Carlos Egues, J.
;
Chen, Wei
Total Authors: 4
|
| Document type: | Journal article |
| Source: | PHYSICAL REVIEW B; v. 107, n. 4, p. 9-pg., 2023-01-03. |
| Abstract | |
When normal metals (NMs) are attached to topological insulators or topological superconductors, it is conceivable that the quantum states in these finite adjacent materials can intermix. In this case-and because the NM usually does not possess the same symmetry as the topological material-it is pertinent to ask whether zero-energy edge states in the topological layer are affected by the presence of the NM. To address this issue, we consider three prototype systems simulated by tight-binding models, namely a Su-Schrieffer-Heeger/NM, a Kitaev/NM, and a Chern insulator/NM. For all junctions investigated, we find that there exist trivial "fine-tuned" zero-energy states in the NM layer that can percolate into the topological region, thus mimicking a topological state. These zero-energy states are created by fine-tuning the NM chemical potential such that some of the NM states cross zero energy; they can occur even when the topological material is in the topologically trivial phase, and exist over a large region of the topological phase diagram. Interestingly, the true Majorana end modes of the Kitaev/NM model cannot be crossed by any NM state, as the NM metal layer in this case does not break particle-hole symmetry. On the other hand, when the chiral symmetry of the Su-Schrieffer-Heeger chain is broken by the attached NM, crossings are allowed. In addition, even in Chern insulators that do not preserve nonspatial symmetries, but the topological edge state self-generates a symmetry eigenvalue, such a fine-tuned zero-energy state can still occur. Our results indicate that when a topological material is attached to a metallic layer, one has to be cautious as to identify true topological edge states merely from their energy spectra and wave function profiles near the interface. (AU) | |
| FAPESP's process: | 20/00841-9 - Shubnikov-de-Haas oscillations in topological and non-topological electron systems |
| Grantee: | José Carlos Egues de Menezes |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 16/08468-0 - Topological insulators and Majorana fermions |
| Grantee: | José Carlos Egues de Menezes |
| Support Opportunities: | Regular Research Grants |