In-plane topological p-n junction in the three-dimensional topological insulator Bi2-xSbxTe3-ySey

Ngoc Han Tu; Yoichi Tanabe; Yosuke Satake; Khuong Kim Huynh; Katsumi Tanigaki

doi:10.1038/ncomms13763

In-plane topological p-n junction in the three-dimensional topological insulator Bi_2-xSb_xTe_3-ySe_y

Nat Commun. 2016 Dec 9:7:13763. doi: 10.1038/ncomms13763.

Authors

Ngoc Han Tu¹, Yoichi Tanabe¹, Yosuke Satake¹, Khuong Kim Huynh², Katsumi Tanigaki^{1

2}

Affiliations

¹ Department of Physics, Graduate School of Science, Tohoku University, 6-3 Aramaki, Aoba-ku, Sendai, Miyagi 980-8577, Japan.
² WPI-Advanced Institute for Materials Research, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8578, Japan.

Abstract

A topological p-n junction (TPNJ) is an important concept to control spin and charge transport on a surface of three-dimensional topological insulators (3D-TIs). Here we report successful fabrication of such TPNJ on a surface of 3D-TI Bi_2-xSb_xTe_3-ySe_y thin films and experimental observation of the electrical transport. By tuning the chemical potential of n-type topological Dirac surface of Bi_2-xSb_xTe_3-ySe_y on its top half by using tetrafluoro-7,7,8,8-tetracyanoquinodimethane as an organic acceptor molecule, a half surface can be converted to p-type with leaving the other half side as the opposite n-type, and consequently TPNJ can be created. By sweeping the back-gate voltage in the field effect transistor structure, the TPNJ was controlled both on the bottom and the top surfaces. A dramatic change in electrical transport observed at the TPNJ on 3D-TI thin films promises novel spin and charge transport of 3D-TIs for future spintronics.

Publication types

Research Support, Non-U.S. Gov't