Charge Density Waves in Transition Metal Dichalcogenides

I will present some of our recent work [1-5] on the understanding of the electronic properties of layered materials and their 2D relatives by means of first principles electronic structure calculations.

In particular, the presentation will focus on the correlation between the crystal structure and the electronic properties, with special emphasis on the structural instabilities which have an electronic origin.

This will be done in connection with recent experimental studies that have been able to demonstrate the presence of charge density waves (CDW) in several 2D single-layer materials like NbSe2 and TiSe2 and TiTe2. For NbSe2, we have focused on the nature and atomic displacements associated with the CDW. The evolution of the CDW with external electrostatic doping, which has been achieved experimentally using field effect transistor setups, will be analysed for the case of TiSe2 [4]. For the case of TiTe2, we focus on the recently observed CDW in the single layer, which is not present in the bulk material [5].

References

[1] Y. Noat, J. A. Silva-Guillén, T. Cren, V. Cherkez, C. Brun, S. Pons, F. Debontridder, D.     Roditchev, W. Sacks, L. Cario, P. Ordejón, A. García, and E. Canadell, Phys. Rev. B 92     (2015) 134510
[2] J. A. Silva-Guillén, P. Ordejón, F. Guinea and E. Canadell, 2D Mater. 3 (2016) 035028
[3] J A Silva-Guillén, E Canadell, P Ordejón, F. Guinea and R Roldán, 2D Mater. 4 (2017)     025085
[4] B. Guster, M. Pruneda, E. Canadell, P. Ordejón, 2D Mater. 5 (2018) 025024
[5] B. Guster, E. Canadell, R. Robles, M. Pruneda, P. Ordejon, to be published