Lattice deformations and spin-orbit effects in two dimensional materials

Resumen

By two-dimensional (2D) crystals we denote a wide family of novel materials[1] among which graphene[2] is the paradigm. Since the 70¿s and thanks to the ultrahigh vacuum technology it has been possible to grow very thin crystals, even one atom thick. However, these solids were metastable in the best scenario, which means, essentially, that only could survive on the metallic substrate where they grew. Of course, this prevented any potential application, and even a careful characterization. The discovery of graphene in 2004,[3] a single layer of carbon atoms arranged in a honeycomb lattice, constituted a complete revolution in this research line and a milestone in Solid State Physcis. Two different families are usually distinguished among the allotropes of carbon: diamond, unique and very hard, which is a band insulator, and graphite, a semiconductor with multiple applications which goes from pencils to nuclear reactors. Graphite is composed of graphene layers weakly coupled by Van der Waals forces. Geim and Novoselov and their collaborators in the University of Manchester were able to exfoliate graphite down to a single layer. This single layer is mechanically stable and can be transferred to different substrates. Moreover, its transport properties improve when part of the substrate is removed and a portion of the graphene sample remains suspended