Merging Dirac electrons and correlation effect in the heterostructured Bi2Te3/Fe1+dTe

TL;DR

This study reports the observation of Dirac electrons and correlation effects coexisting in a heterostructure of Bi2Te3 and Fe1+dTe, revealing new physics at the intersection of topological insulators and correlated electron systems.

Contribution

It demonstrates the experimental merging of Dirac electrons and strong correlation effects in a heterostructure, a novel combination in condensed matter physics.

Findings

Quantum oscillation of Landau levels observed in Bi2Te3 films.

Gapped feature at Fermi energy indicating correlation effects.

Challenging existing theories on topological insulators with strong correlations.

Abstract

The topological insulator and strong electronic correlation effect are two important subjects in the frontier studies of modern condensed matter physics. A topological insulator exhibits a unique pair of surface conduction bands with the Dirac dispersion albeit the bulk insulating behaviour. These surface states are protected by the topological order, and thus the spin and momentum of these surface electrons are locked together demonstrating the feature of time reversal invariance. On the other hand, the electronic correlation effect becomes the very base of many novel electronic states, such as high temperature superconductivity, giant magnetoresistance etc. Here we report the discovery of merging the two important components: Dirac electrons and the correlation effect in heterostructured Bi2Te3/Fe1+dTe. By measuring the scanning tunneling spectroscopy on Bi2Te3 thin films (a typical topological insulator) thicker than 6 quintuple layers on top of the Fe1+dTe single crystal (a parent phase of the iron based superconductors FeSe1-xTex), we observed the quantum oscillation of Landau levels of the Dirac electrons and the gapped feature at the Fermi energy due to the correlation effect of Fe1+dTe. Our observation challenges the ordinary understandings and must demonstrate some unexplored territory concerning the combination of topological insulator and strong correlation effect.