Band structure of monolayer <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>1</mml:mn><mml:mi>T</mml:mi><mml:mtext>−</mml:mtext><mml:msub><mml:mi>TiS</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math> and its implications for the phase diagrams of Ti-based transition metal dichalcogenides

Summary

The search for two-dimensional semiconductors with novel physical properties is a key to developing functional nanoelectronic devices. We have succeeded in fabricating a monolayer ${\mathrm{TiS}}_{2}$ film on bilayer graphene/SiC(0001) by combining the molecular-beam epitaxy and the topotactic chemical reaction, and clarified the electronic states by angle-resolved photoemission spectroscopy and first-principles calculations. We found that monolayer ${\mathrm{TiS}}_{2}$ takes the octahedral $1T$ structure with an indirect semiconducting band gap of about 1 eV. We also found that monolayer $1T\text{\ensuremath{-}}{\mathrm{TiS}}_{2}$ shows no indication of $2\ifmmode\times\else\texttimes\fi{}2$ charge-density wave (CDW) in contrast to isostructural family compounds, monolayer ${\mathrm{TiSe}