Atomically Abrupt Topological p–n Junction

5 years ago

Atomically Abrupt Topological p–n Junction

Han Woong Yeom, Byeong-Gyu Park, Kyung-Hwan Jin, Feng Liu, Sung Hwan Kim, Byung Woo Kho, Jun Sung Kim

Topological insulators (TI’s) are a new class of quantum matter with extraordinary surface electronic states, which bear great potential for spintronics and error-tolerant quantum computing. In order to put a TI into any practical use, these materials need to be fabricated into devices whose basic units are often p–n junctions. Interesting electronic properties of a ‘topological’ p–n junction were proposed theoretically such as the junction electronic state and the spin rectification. However, the fabrication of a lateral topological p–n junction has been challenging because of materials, process, and fundamental reasons. Here, we demonstrate an innovative approach to realize a p–n junction of topological surface states (TSS’s) of a three-dimensional (3D) topological insulator (TI) with an atomically abrupt interface. When a ultrathin Sb film is grown on a 3D TI of Bi₂Se₃ with a typical n-type TSS, the surface develops a strongly p-type TSS through the substantial hybridization between the 2D Sb film and the Bi₂Se₃ surface. Thus, the Bi₂Se₃ surface covered partially with Sb films bifurcates into areas of n- and p-type TSS’s as separated by atomic step edges with a lateral electronic junction of as short as 2 nm. This approach opens a different avenue toward various electronic and spintronic devices based on well-defined topological p–n junctions with the scalability down to atomic dimensions.

Publisher URL: http://dx.doi.org/10.1021/acsnano.7b03880

DOI: 10.1021/acsnano.7b03880