Department of Physics, Graduate School of Science, Tohoku University, 6-3 Aramaki, Aoba-ku, Sendai, Miyagi 980-8577, Japan.
WPI-Advanced Institute for Materials Research, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8578, Japan.
Nat Commun. 2016 Dec 9;7:13763. doi: 10.1038/ncomms13763.
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 BiSbTeSe thin films and experimental observation of the electrical transport. By tuning the chemical potential of n-type topological Dirac surface of BiSbTeSe 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.
拓扑 p-n 结（TPNJ）是控制三维拓扑绝缘体（3D-TI）表面自旋和电荷输运的重要概念。在这里，我们成功地在 3D-TI BiSbTeSe 薄膜的表面上制造了这种 TPNJ，并对其进行了电输运实验观察。通过使用四氟-7,7,8,8-四氰基对苯醌二甲烷作为有机受主分子来调节 BiSbTeSe 的 n 型拓扑狄拉克表面的化学势，一半表面可以被转化为 p 型，而另一半表面则保持为相反的 n 型，从而可以创建 TPNJ。通过在场效应晶体管结构中扫回栅极电压，可以控制 TPNJ 在底部和顶部表面上的状态。在 3D-TI 薄膜上的 TPNJ 观察到的电输运的显著变化，为未来的自旋电子学提供了三维拓扑绝缘体的新颖自旋和电荷输运。
