2017/09/30 by Farzad Mahfouzi, Jinwoong Kim, Jin Woong Kim +1
Chemistry · Engineering · Physics and Astronomy · #Ab initio #Ab initio quantum chemistry methods #Advanced Memory and Neural Computing #Bilayer #Chemistry #Condensed matter physics #Dephasing #Formalism (music) #Magnetic properties of thin films #Molecule #Physics #Quantum #Quantum and electron transport phenomena #Quantum mechanics #Spin (aerodynamics) #Thermodynamics #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevb.96.214421
published as Phys. Rev. B 96, 214421 (2017) · 8 pages, 5 figures
openalex created_date 2017/09/25 · arxiv created 2017/11/14 · openalex publication_date 2017/12/15 · arxiv updated 2017/12/20 · openalex updated_date 2026/08/06
A fully quantum-mechanical description of the precessional damping of a Pt/Co bilayer is presented in the framework of the Keldysh Green's function approach using ab initio electronic structure calculations. In contrast to previous calculations of classical Gilbert damping (\ensuremathαGD), we demonstrate that \ensuremathαGD in the quantum case does not diverge in the ballistic regime due to the finite size of the total spin S. In the limit of S\ensuremath→\ensuremath∞ we show that the formalism recovers the torque correlation expression for \ensuremathαGD which we decompose into spin-pumping and spin-orbital torque correlation contributions. The formalism is generalized to take into account a self-consistently determined dephasing mechanism which preserves the conservation laws and allows the investigation of the effect of disorder. The dependence of \ensuremathαGD on Pt thickness and disorder strength is calculated, and the spin-diffusion length of Pt and the spin mixing conductance of the bilayer are determined and compared with experiments.