Strain, Lattice, Interactions and Entanglement in novel Two-Dimensional materials

Funding Body: MC-CIG – Support for training and career development of researcher (CIG)
(2013-2016) cordis
Emmanuele Cappelluti
The isolation of graphene in 2004 has triggered the most promising expectations in the field of condensed matter. One of the main drawbacks for realistic application is however the lack of a band gap in single layer compounds. To overcome this shortcoming, alternative two-dimensional materials, like MoS2 and other dichalcogenides, are recently becoming popular, with the advantage of presenting an intrinsic gap. One of the interesting aspects of these materials is the possibility of modulating the electronic properties by means of controlled external sources, as for instance strain and other
lattice effects. The scenario is here much richer and promising than graphene since the valleys degrees of freedom are here strongly entangled with the spin and with the orbital degrees of freedom, suggesting that new channels to manipulate the electronic, transport, optical properties of these materials are here possible.
In this project we will investigate at the microscopic level the fundamental physical mechanisms that control the electronic, transport and optical properties of these layered materials. Motivated by the evidence that pressure and strain can induce sizable remarkable effects on the band structure, we will address the issue of the electron-lattice coupling in a wider context, investigating how these effects are operative at a local scale, how they will depend on the number of layers and their stacking order, on external electric fields, etc. Probably even more interesting, motivated by the strong entanglement between charge/lattice/spin/orbital degrees of freedom, is the study how the manipulation of one different degree can tune the other ones. Objective of the program is to identify suitable specific mechanisms of tunable interplay between the different degrees of freedom and to investigate at the largest possible extent their physical properties.