Macro- and atomic-scale observations of a one-dimensional heterojunction in a nickel and palladium nanowire complex.

Wakizaka, Masanori; Kumagai, Shohei; Wu, Hashen; Sonobe, Takuya; Iguchi, Hiroaki; Yoshida, Takefumi; Yamashita, Masahiro; Takaishi, Shinya · Nat Commun · 2022

basic_science · Level V

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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)<sub>2</sub>Br]Br<sub>2</sub> (1; chxn = 1R-2R-diaminocyclohexane) and a 1D Peierls or charge-density-wave insulator [Pd(chxn)<sub>2</sub>Br]Br<sub>2</sub> (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.