Recent advances in photoemission spectroscopy: Nano-ARPES and Spin Resolved ARPES. The new Spin-ARPES instrument at IMDEA Nanociencia.

Link: https://nanoscience-imdea.zoom.us/j/97129833381?pwd=QnJ5OEt0VEhtVzM4TG

Abstract:

Spin and Angle-Resolved Photoemission Spectroscopy (SR-ARPES) is a fundamental tool to visualize the momentum and (spin-dependent) electronic bands of materials. The significant progress in energy and momentum resolution makes of this technique a highly sophisticated approach to characterize the electronic states of complex 2D materials and strongly correlated systems.

The nano-ARPES technique focalizes the photon beam on sample areas of the order of up to hundreds of nanometers, allowing the study of the electronic structure in sample domain sizes that conventional ARPES cannot reach. Nano-ARPES measurements on quasi-1D NbSe₃ micro-fibers will be presented, revealing the electronic band structure at the 2^nd charge density wave phase of this material (1).

Adding up spin resolution, allows the complete determination of a quantum state. Spin measurements can be specially interesting in systems with strong spin-orbit coupling (SOC) (2), that can give rise to relevant spin polarized electronic surface states, such as Rashba or topological states. I will present the instrumentation and capabilities of the new SR-ARPES system recently installed at IMDEA and the fist results on the Rashba surface state of Au(111).

Finally, I will review recent results for a molecular approach for engineering interfacial interactions in magnetic/topological Insulator heterostructures, where a monolayer of Co-porphyrin based system is interfaced to a prototypical topological insulator, Bi₂Te₃. The electronic band structure is complemented with structural characterization (STM), local electronic properties (STS), and magnetic properties (XMCD).

(1) M. A. Valbuena et al. Phys. Rev. B Phys. Rev. B 99, 075118.

(2) M. G. Cuxart, M. A. Valbuena, et al. ACSNano 2020, 14, 6285−6294