Seminars Archive

Manipulation of charge density waves in NbSe₂ by atom adsorption

Abstract
Transition metal dichalcogenides (TMdCs) have been the focus of intensive research, for their topological properties, superconducting transition and charge density wave (CDW) transition. In single layers, electronic properties may be modified considerably due to the loss of a centre of symmetry and the absence of a coterminous for van der Waals interactions. In particular, large debate over the structural details of the CDW in NbSe₂ have been reported. Moreover, exposure to metallic adsorbates manipulates structural instabilities. By means of ab-initio calculations, we study the structure of pristine and doped NbSe₂ single layers, finding triangularly modulated structures preferred to hexagonally modulated ones, as reported very recently. Moreover, we show how Co, Mn, K and Ga modify the energy hierarchy of the CDWs and the charge distribution. In particular, Co and Mn favour hexagonally modulated structures, while K and Ga still support a triangular modulated structure. Moreover, we observe an incipient stripe phase which may be connected to recent experimental observations.