Probing two-dimensional materials using focused angle-resolved photoemission spectroscopy

Abstract: Two-dimensional (2D) materials offer the freedom to create novel condensed matter systems, with unique properties, by mechanically assembling different (or same) 2D materials layer-by-layer to form atomically sharp vertical or lateral heterostructures. The van der Waals (vdW) heterostructures with small lattice mismatch and a relatively small twist angle between the constituent layers, have shown to exhibit coexisting complex phases of matter including Mott insulating state, superconductivity, bound quasiparticles, and topological states. In addition, the extreme surface sensitivity of two-dimensional (2D) materials provides an unprecedented opportunity to engineer the physical properties of these materials using external perturbations. In this talk, I will discuss the utilization of angle-resolved photoemission spectroscopy (ARPES) with high spatial resolution to investigate the electronic band structure of 2D heterostructures and their devices. This can shed light on the intricate relationship between controlled external perturbations, substrate, and electronic properties of 2D materials [1, 2]. In particular, I will discuss our in-operando nanoARPES results that exhibit highly tunable many-body effects in graphene devices [3] and tunable van Hove singularities in twisted bilayer graphene [4].

References: [1] Katoch et. al., Nature Physics 14, 355-359 (2018). [2] Ulstrup, et. al., Science Advances, Vol. 6, no. 14, eaay6104, (2020). [3] Muzzio, et. al., Physical review B Rapid Communications 101, 201409(R) (2020). [4] Jones, et. al., Adv. Mater. 2020, 32, 2001656.

cosmology and nongalactic astrophysicsother condensed matterquantum gasesstrongly correlated electronssuperconductivitygeneral relativity and quantum cosmologyHEP - theory

Audience: researchers in the topic

Carnegie Mellon theoretical physics