Title: Graphene spintronics - relaxation and proximity
Speaker: Dr. Denis Kochan (Institute of Physics, Slovak Academy of Sciences)
Time: 2023/5/24 (Wed.) 14:00
Venue: NCTS Phys. Lecture Hall, 4F, Cosmology Hall, NTU

Abstract:
Graphene and other novel 2D materials offer new perspectives for
spintronic applications.  One important spintronic characteristic to
judge is spin relaxation. In graphene the electron spin lifetime is
surprisingly short. Because of small intrinsic spin-orbit coupling the
underlying mechanism for spin relaxation had been an outstanding
puzzle. We tackled that problem and showed that the main culprits are
resonant magnetic impurities [1]. Despite lacking a band gap, graphene
is very versatile for its functionalization, e.g., by adatoms [2] , or
by a proximity to two-dimensional transition-metal dichalcogenides
(TMDC) [3]. We have shown  [4] that graphene on WSe2 exhibits an
inverted band structure, which leads to pseudohelical edge states.
Another interesting topic is superconducting coherence. In the last
part of my talk, I will discuss unique and surprising spin relaxation
characteristics of graphene proximitized by s-wave superconductors
[5].

[1]      D. Kochan, M. Gmitra, and J. Fabian, Phys. Rev. Lett. 112, 116602 (2014).
[2]      M. Gmitra, D. Kochan, and J. Fabian, Phys. Rev. Lett. 110, 246602 (2013).
[3]      M. Gmitra, D. Kochan, P. Högl, and J. Fabian, Phys. Rev. B 93, (2016).
[4]      T. Frank, P. Högl, M. Gmitra, D. Kochan, and J. Fabian, Phys. Rev. Lett. 120, 156402 (2018).
[5]      D. Kochan, M. Barth, A. Costa, K. Richter, J. Fabian, Phy. Rev. Lett. 125, 087001 (2020)