STM on 2D quantum materials

Two-dimensional materials such as graphene and transition metal dichalcogenides are envisioned as ideal building blocks for material’s engineering with single-atomic-plane precision. Their layered structure enables exfoliation down to the monolayer limit and subsequent stacking and twisting to form heterostructures with novel properties that are absent in the individual layers. Recent progress in the field has demonstrated that the combination of the constituents is as relevant as the rotational angle between their atomic lattices for their performance. The first and probably most exciting example, where the twist angle leads to properties not known in the parent compound, is so-called magic-angle graphene. At different occupation of the bands, the properties range from a correlated insulator to a superconductor.

We use low-temperature (~300 mK) STM/STS to study the correlated phases that emerge in such two-dimensional and moiré systems. STM accesses atomic and electronic structures simultaneously through topography and local density of states mapping. With such powerful combinations of high spatial and energy resolution we would like, for example, to understand the mechanism behind the superconducting state in magic-angle graphene.

We are also interested in other two-dimensional systems with rich phase diagrams, such as rhombohedral graphene. Monolayer and twisted transition metal dichalcogenides also present fascinating phenomenology with Mott insulators, Wigner crystals or spin liquids as examples of some of the phases expected to arise.

Positions Available: This group will start in Spring 2023 and will have opportunities for outstanding postdoctoral researchers, PhD students, master and bachelor students and interns, interested in the study of 2D systems by low-temperature STM. For enquiries, please contact Prof. Carmen Rubio-Verdú