Starting from a single layer of NbS2 grown on graphene by molecular beam epitaxy, the single unit cell thick 2D materials Nb5/3S3-2D and Nb2S3-2D are created using two different pathways. Either annealing under sulfur-deficient conditions at progressively higher temperatures or deposition of increasing amounts of Nb at elevated temperature result in phase-pure Nb5/3S3-2D followed by Nb2S3-2D. The materials are characterized by scanning tunneling microscopy, scanning tunneling spectroscopy and X-ray photoemission spectroscopy. The experimental assessment combined with systematic density functional theory calculations reveals their structure. The 2D materials are covalently bound without any van der Waals gap. Their stacking sequence and structure are at variance with expectations based on corresponding bulk materials highlighting the importance of surface and interface effects in structure formation.
@article{arxiv.2407.17655,
title = {Engineering two-dimensional materials from single-layer NbS$_2$},
author = {Timo Knispel and Daniela Mohrenstecher and Carsten Speckmann and Affan Safeer and Camiel van Efferen and Virgínia Boix and Alexander Grüneis and Wouter Jolie and Alexei Preobrajenski and Jan Knudsen and Nicolae Atodiresei and Thomas Michely and Jeison Fischer},
journal= {arXiv preprint arXiv:2407.17655},
year = {2024}
}