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凝態理論seminar

Graphene Spintronics: Relaxation and Proximity

演講者 : Prof. Denis Kochan - (Institute of Physics, Slovak Academy of Sciences)
演講時間 : 2023 / 05 / 17 16:00
理學教學新大樓物理系 5F 36567會議室
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).