Honeycomb-Lattice Mott insulator on Tantalum Disulphide
Abstract
Effects of electron many-body interactions amplify in an electronic system with a narrow bandwidth opening a way to exotic physics. A narrow band in a two-dimensional (2D) honeycomb lattice is particularly intriguing as combined with Dirac bands and topological properties but the material realization of a strongly interacting honeycomb lattice described by the Kane-Mele-Hubbard model has not been identified. Here we report a novel approach to realize a 2D honeycomb-lattice narrow-band system with strongly interacting 5 electrons. We engineer a well-known triangular lattice 2D Mott insulator 1T-TaS into a honeycomb lattice utilizing an adsorbate superstructure. Potassium (K) adatoms at an optimum coverage deplete one-third of the unpaired electrons and the remaining electrons form a honeycomb lattice with a very small hopping. Ab initio calculations show extremely narrow Z topological bands mimicking the Kane-Mele model. Electron spectroscopy detects an order of magnitude bigger charge gap confirming the substantial electron correlation as confirmed by dynamical mean field theory. It could be the first artificial Mott insulator with a finite spin Chern number.
Keywords
Cite
@article{arxiv.2007.06302,
title = {Honeycomb-Lattice Mott insulator on Tantalum Disulphide},
author = {Jinwon Lee and Kyung-Hwan Jin and Andrei Catuneanu and Ara Go and Jiwon Jung and Choongjae Won and Sang-Wook Cheong and Jaeyoung Kim and Feng Liu and Hae-Young Kee and Han Woong Yeom},
journal= {arXiv preprint arXiv:2007.06302},
year = {2020}
}
Comments
6 pages, 3 figures