Atomic Diffusion-Induced Polarization and Superconductivity in Topological Insulator-Based Heterostructures.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38126781.
- Also identified by DOI 10.1021/acsnano.3c08601 and PMC identifier 10786152.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The proximity effect at a highly transparent interface of an <i>s</i>-wave superconductor (S) and a topological insulator (TI) provides a promising platform to create Majorana zero modes in artificially designed heterostructures. However, structural and chemical issues pertinent to such interfaces have been poorly explored so far. Here, we report the discovery of Pd diffusion-induced polarization at interfaces between superconductive Pd<sub>1+<i>x</i></sub>(Bi<sub>0.4</sub>Te<sub>0.6</sub>)<sub>2</sub> (<i>x</i>PBT, 0 ≤ <i>x</i> ≤ 1) and Pd-intercalated Bi<sub>2</sub>Te<sub>3</sub> by using atomic-resolution scanning transmission electron microscopy. Our quantitative image analysis reveals that nanoscale lattice strain and QL polarity synergistically suppress and promote Pd diffusion at the normal and parallel interfaces, formed between Te-Pd-Bi triple layers (TLs) and Te-Bi-Te-Bi-Te quintuple layers (QLs), respectively. Further, our first-principles calculations unveil that the superconductivity of the <i>x</i>PBT phase and topological nature of the Pd-intercalated Bi<sub>2</sub>Te<sub>3</sub> phase are robust against the broken inversion symmetry. These findings point out the necessity of considering the coexistence of electric polarization with superconductivity and topology in such S-TI systems.