Macro- and atomic-scale observations of a one-dimensional heterojunction in a nickel and palladium nanowire complex
Masanori Wakizaka, Shohei Kumagai, Hashen Wu, Takuya Sonobe, Hiroaki Iguchi, Takefumi Yoshida, Masahiro Yamashita, Shinya Takaishi
Abstract
Abstract The creation of low-dimensional heterostructures for intelligent devices is a challenging research topic; however, macro- and atomic-scale connections in one-dimensional (1D) electronic systems have not been achieved yet. Herein, we synthesize a heterostructure comprising a 1D Mott insulator [Ni(chxn) 2 Br]Br 2 ( 1 ; chxn = 1 R -2 R -diaminocyclohexane) and a 1D Peierls or charge-density-wave insulator [Pd(chxn) 2 Br]Br 2 ( 2 ) using stepwise electrochemical growth. It can be considered as the first example of electrochemical liquid-phase epitaxy applied to molecular-based heterostructures with a macroscopic scale. Moreover, atomic-resolution scanning tunneling microscopy images reveal a modulation of the electronic state in the heterojunction region with a length of five metal atoms (~ 2.5 nm), that is a direct evidence for the atomic-scale connection of 1 and 2 . This is the first time that the heterojunction in the 1D chains has been shown and examined experimentally at macro- and atomic-scale. This study thus serves as proof of concept for heterojunctions in 1D electronic systems.