# Electronic structure of Bi2Te3/FeTe heterostructure: implications for unconventional superconductivity

## TL;DR

This study uses angle-resolved photoemission spectroscopy to investigate the electronic structure of a Bi2Te3/FeTe heterostructure, revealing charge transfer at the interface that may be key to its unconventional superconductivity.

## Contribution

It provides new insights into the electronic interactions at the Bi2Te3/FeTe interface and their role in inducing superconductivity in the heterostructure.

## Key findings

- Dirac-cone surface state shifts to higher binding energy
- Holelike band from FeTe shifts to lower binding energy
- Charge transfer from FeTe to Bi2Te3 observed

## Abstract

We have performed angle-resolved photoemission spectroscopy on a heterostructure consisting of topological insulator Bi2Te3 and iron chalcogenide FeTe fabricated on SrTiO3 substrate by molecular-beam-epitaxy technique. This system was recently found to show superconductivity albeit non-superconducting nature of each constituent material. Upon interfacing FeTe with two quintuple layers of Bi2Te3, we found that the Dirac-cone surface state of Bi2Te3 is shifted toward higher binding energy, while the holelike band at the Fermi level originating from FeTe moves toward lower binding energy. This suggests that electron charge transfer takes place from FeTe to Bi2Te3 through the interface. The present result points to importance of hole-doped FeTe interface for the occurrence of unconventional superconductivity.