Beyond the Generalized Kadanoff-Baym Ansatz

0521815 - FZÚ 2020 RIV DE eng J - Journal Article
Kalvová, Anděla - Velický, B. - Špička, Václav
Beyond the Generalized Kadanoff-Baym Ansatz.
Physica Status Solidi B. Roč. 256, č. 7 (2019), s. 1-8, č. článku 1800594. ISSN 0370-1972. E-ISSN 1521-3951
Institutional support: RVO:68378271
Keywords : Generalized Kadanoff-Baym Ansatz * molecular bridges * non-equilibrium * transient magnetic currents
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 1.481, year: 2019
Method of publishing: Limited access
https://doi.org/10.1002/pssb.201800594

The study of electron transport is easier if the Kadanoff–Baym equations(KBE) are simplified using the Generalized Kadanoff–Baym Ansatz (GKBA).For molecular bridges, GKBA is known to safely work for weakand flat tunneling functions. It fails, if either of the conditions is not satisfied.The case in point is a molecular bridge formed by an Anderson type local center treated in the mean field and linked by tunneling junctions to two ferromagnetic electrodes whose tunneling functions simulate nickel with complex sd structure. Transient magnetic currents under a constant galvanic bias between electrodes are invoked by sudden switching on of both junctions. We establish quantitative criteria for the validity of the Ansatz, to develop a practically tractable correction to the Ansatz working beyond its validity range. The corrections to the Ansatz are obtained as a stationary approximation to the vertex part of the exact reconstruction equations whose free term is the standard GKBA.
Permanent Link: http://hdl.handle.net/11104/0306377