Naslov
Nonadiabatic effects in graphene based materials

Autori
Girotto, Nina ; Novko, Dino

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, neobjavljeni rad, znanstveni

Skup
Graphene2021

Mjesto i datum
Grenoble, Francuska, 26.10.2021. - 29.10.2021

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
phonon, electron-phonon interaction, DFT, nonadiabaticity

Sažetak
Some of the most prominent features of quasi two dimensional (Q2D) materials issue from the electron-phonon coupling (EPC) and are easily tailored by strain and doping. Phonon mediated superconductivity is expected in a variety of Q2D materials, and because the transition temperature within the Bardeen-Cooper-Schrieffer (BCS) theory increases with increasing EPC, tailoring EPC provides a recipe for a more feasible realization of superconductors. First-principles density functional theory (DFT) calculations of EPC properties of doped 2D systems, specifically highly doped graphene and hole doped graphane (hydrogenated graphene), will hereby be presented. Doping equalizes the energy scales of electron transitions and phonon frequencies, but using the adiabatic Born-Oppenheimer approximation, DFT assumes nuclear and electronic motion can be separated. It will be shown that the mentioned approximation is not applicable on studied systems, since the adiabatically obtained phonon spectrum is at significant variance with the one containing nonadiabatic corrections. Non-adiabatic renormalization greatly modifies the EPC coupling strength, which in turn alters the transition temperature prediction, rendering its calculation much more reliable. The importance of including the dynamical corrections is undisputable and care should be taken when neglecting nonadiabatic effects as they have a huge impact not only on the magnitude of EPC strength and the transition temperature, but also on the qualitative understanding of the system in question.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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