Competing orders in transition metal dichalcogenides approaching the 2D limitan ab initio study

Resumo

In this Thesis we have studied the interplay between electronic, magnetic and structural degrees of freedom in 2D transition metal dichalcogenides from a theoretical point of view. This is exemplified by the complex competition between structural distortion in the form of charge-density waves and magnetism in Cr-based compounds; by the appearance of strongcorrelation effects caused by the star-of-David charge density wave in Ta-based monolayers; and the rise of a ferroelectric order caused by yet a different type of charge-density wave in MoTe2. Our calculations also provide a way to characterize a recently discovered phase of NbSeTe, that naturally occurs as an ordered heterostructure in bulk form. The work shows the enormous potential of TMD's as building blocks for engineering new materials on the nanoscale.