Abstract
We present a method to calculate from first principles the spin Seebeck effect on finite systems. Our method, which is suited for all ab initio, quantum-chemistry-based results, is demonstrated quasianalytically on the dimer. To this end we start from the analytical solutions of the many-body wave function for the minimal molecule and propagate it numerically in time using the Liouville-von Neumann equation of motion. The system is coupled to two baths with different temperatures, described with a Lindblad superoperator. We mainly focus on the concept of how to divide any operator into several spatially localized contributions and show that the spatial localization of the virtual excitations (i.e., splitting of the ladder operators into two sets of localized operators with different eigenbases) is the underlying reason for the spin Seebeck effect. Last but not least, we analyze the entanglement of the system and find that the maxima of the Laplacian of the negativity coincide with the change of the direction of the spin Seebeck effect.
- Received 22 March 2016
- Revised 29 September 2016
DOI:https://doi.org/10.1103/PhysRevB.94.144433
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