Self-assembled honeycomb lattice in the monolayer of cyclic thiazyl diradical BDTDA (= 4,4'-bis(1,2,3,5-dithiadiazolyl)) on Cu(111) with a zero-bias tunneling spectra anomaly

Masayuki Yamamoto; Rie Suizu; Sudipta Dutta; Puneet Mishra; Tomonobu Nakayama; Kazuyuki Sakamoto; Katsunori Wakabayashi; Takashi Uchihashi; Kunio Awaga

doi:10.1038/srep18359

Self-assembled honeycomb lattice in the monolayer of cyclic thiazyl diradical BDTDA (= 4,4'-bis(1,2,3,5-dithiadiazolyl)) on Cu(111) with a zero-bias tunneling spectra anomaly

Sci Rep. 2015 Dec 17:5:18359. doi: 10.1038/srep18359.

Authors

Masayuki Yamamoto^{1

2}, Rie Suizu^{1

3}, Sudipta Dutta², Puneet Mishra², Tomonobu Nakayama², Kazuyuki Sakamoto^{1

3}, Katsunori Wakabayashi², Takashi Uchihashi², Kunio Awaga^{4

3}

Affiliations

¹ Department of Nanomaterials Science, Graduate School of Advanced Integration Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
² International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
³ CREST, JST, 4-1-8 Honcho, Kawaguchi 332-0012, Japan.
⁴ Department of Chemistry and Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.

Abstract

Scanning tunneling microscopy (STM) observation reveals that a cyclic thiazyl diradical, BDTDA (= 4,4'-bis(1,2,3,5-dithiadiazolyl)), forms a well-ordered monolayer honeycomb lattice consisting of paramagnetic corners with unpaired electrons on a clean Cu(111) surface. This BDTDA lattice is commensurate with the triangular lattice of Cu(111), with the former being 3 × 3 larger than the latter. The formation of the BDTDA monolayer structure, which is significantly different from its bulk form, is attributed to an interaction with the metal surface as well as the intermolecular assembling forces. STM spectroscopy measurements on the BDTDA molecules indicate the presence of a characteristic zero-bias anomaly centered at the Fermi energy. The origin of this zero-bias anomaly is discussed in terms of the Dirac cones inherent to the honeycomb structure.

Publication types

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