Quantum Well States for Graphene Spin-Texture Engineering

Session

PST.2 - Microscopy for the study of quantum effects and nano-optics

Authors

Dr Thomas Vincent (4), Prof Elena Voloshina (1, 3, 5), Dr Stephane Pons (4), Dr Sabina Simon (2), Prof Mikhail Fonin (2), Dr Kangli Wang (3), Prof Beate Paulus (3), Prof Yuriy Dedkov (1, 5), Prof Dimitri Roditchev (4), Dr Sergio Vlaic (4)

Affiliations

1. Department of Physics, Shanghai University, 99 Shangda Road, 200444 Shanghai, China
2. Department of Physics, University of Konstanz, 78457 Konstanz, Germany
3. Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany
4. Laboratoire de Physique et d’Étude des Matériaux, ESPCI Paris, PSL Research University, CNRS, UMR 8213, Sorbonne Universités, UPMC Univ. Paris 06, 75005 Paris, France
5. Institute of Physical and Organic Chemistry, Southern Federal University, 344090 Rostov on Don, Russia

Keywords

ARPES 

Graphene

Spin-Orbit

Abstract text

Since the discovery of the exceptional electronic features of graphene (gr) a great challenge for solid state physics and material science has been to expand its functionalities by the introduction of novel properties [1]. Recently, a strong attention has been devoted to the use of graphene for spintronic applications, with the ultimate goal of manipulating the spin by external electric field [2].  In fact, being made by a light element such as carbon, graphene presents a weak intrinsic spin-orbit interaction, while its enhancement is expected to pave the way to a multitude of exotic phenomena, such as quantum spin Hall effect [3] and possible applications as spin injectors or spin filters [4].

One of the most used approach to induce or/and enhance the spin-orbit interaction in graphene has been by proximity with metallic compounds. Several studies have identified a spin separation of graphene bands up to 100 meV, when graphene is supported on magnetic materials or on heavy metal compounds [5]. It has to be noticed that, so far, the scientific effort has been focused on interfacing graphene with metals which possess strong (e. g., Co and Ni) or weak (e. g., Au, Pt, Ir) interaction with carbon atoms. 

Here, we present a different approach, focusing our attention on graphene placed on Pd [6]. In such a case, the gr-Pd interaction lies in between to what is considered strongly (e.g., C-Co) and weekly interacting (e.g., C-Pt).  We investigate the modification of the electronic structure of graphene (gr) initially grown on Ir(111) via intercalation of one monolayer Pd by means of angle-resolved photoelectron spectroscopy, scanning tunneling microscopy and density functional theory. We reveal that for the gr/Pd/Ir(111) intercalated system, a spin splitting of graphene π states higher than 200 meV is present near the graphene K point. This spin separation arises from the hybridization of the graphene valence band states with spin-polarized quantum well states of a single Pd layer on Ir(111). Our results demonstrate that the proposed approach on the tailoring of the dimensionality of heavy materials interfaced with a graphene layer might lead to a giant spin−orbit splitting of the graphene valence band states. 

 

References

[1] Pesin, D.; MacDonald, A. H. Nat. Mater. 2012, 11, 409. 


[2] Han, W. et al, Nat. Nanotechnol. 2014, 9, 794. 


[3] Kane, C. L.; Mele, E. J. Phys. Rev. Lett. 2005, 95, 226801. 


[4] Yan, W. et al, Nat. Commun. 2017, 8, 661. 


[5] Rybkin, A. G. et al, Nano Lett. 2018, 18, 1564. 


[6] Vincent, T. et al,  J. Phys. Chem. Lett. 2020 11, 1594.