Előadó: Márkus Bence (SZFI)
Az előadás témája: Ultralong spin lifetime and superconductivity in doped graphene
Az előadás időpontja: 2021. március 2., 10 óra
Helyszín: videokonferencia, https://letsmeet.wigner.hu/szeminarium
Today's great challenges of energy storage and informational technologies require new materials. I report on the preparation and physical properties of Li, Na, Ca, and Yb doped few-layer graphene. We found ultralong (3−27 ns) spin relaxation time in the lithium and sodium doped species , and superconductivity in the Ca and Yb doped materials. The emergence of Fano lineshapes in the G-line Raman spectral region as an indication of strong electron-phonon coupling, attest the high level of doping for all the metals probed. We find that Na dopes solely the monolayer graphene as it is known to be inert against graphitic carbon. In the Ca and Yb doped materials a superconductive phase transition is observed at ∼ 11 K and at ∼ 6 K, respectively, utilizing conventional SQUID magnetometry. Superconductivity is confirmed by the presence of non-linear microwave absorption observed in the ESR spectra. Furthermore, we observed differences in the critical fields of the prepared materials compared to their graphite relatives. The obtained materials might find applications in the field of spintronics, energy storage, and printable superconductive circuits.
 B. G. Márkus, P. Szirmai, K. Edelthalhammer, P. Eckerlein, A. Hirsch, F. Hauke, N. M. Nemes, Julio C. Chacón-Torres, B. Náfrádi, L. Forró, T. Pichler, and F. Simon: Ultralong spin lifetime in light alkali atom doped graphene, ACS Nano 14(6), 7492-7501, 2020.