Berlin 2018 – scientific programme

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DS: Fachverband Dünne Schichten

DS 12: 2D Materials: Session II (joint session DS/CPP/HL)

DS 12.13: Talk

Tuesday, March 13, 2018, 12:45–13:00, H 2032

Theoretical description of photoemission spectroscopy of van der Waals structures — •Bruno Amorim — CeFEMA, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, PT-1049-001 Lisboa, Portugal

I present a general theory to model the angle resolved photoemission spectroscopy (ARPES) of van der Waals (vdW) structures. VdW structures are formed by lattice mismatched and/or misaligned stacked layers of two-dimensional materials and can be commensurate or incommensurate.

The present theory is based on a tight-binding description of the bound electrons and the concept of generalized umklapp processes, being capable of describing both commensurate and incommensurate structures for arbitrary lattice mismatch/misalignment. In this way, the present theory goes beyond previous descriptions of ARPES in incommensurate vdW structures, which are based on continuous, low energy models, which limits their applicability to structures with small lattice mismatch/misalignment.

As an example, I apply the general method to the case of twisted bilayer graphene, obtaining the ARPES bands and ARPES constant energy maps.

The present theory should be useful in correctly interpreting experimental results of ARPES of vdW structures and other system displaying competition between different periodicities, such as density wave phases.