2013/11/08 by Denis Comtesse, Comtesse, Denis, Benjamin Geisler +8
Materials Science · Physics and Astronomy · #Heusler alloys: electronic and magnetic properties #Advanced Thermoelectric Materials and Devices #Magnetic properties of thin films
paper · pdf · doi:10.48550/arxiv.1311.1950
The electronic and magnetic bulk properties of half-metallic Heusler alloys\nsuch as Co2FeSi, Co2FeAl, Co2MnSi and Co2MnAl are\ninvestigated by means of em ab initio calculations in combination with Monte\nCarlo simulations. The electronic structure is analyzed using the plane wave\ncode Quantum Espresso and magnetic exchange interactions are determined using\nthe KKR method. From the magnetic exchange interactions the Curie temperature\nis obtained via Monte Carlo simulations. In addition, electronic transport\nproperties of the trilayer systems consisting of two semi-infinite platinum\nleads and a Heusler layer in between are obtained from the fully relativistic\nKKR method by employing the Kubo-Greenwood formalism. The focus is on\nthermoelectric properties, namely the Seebeck effect and its spin dependence.\nIt turns out that already thin Heusler layers provide highly polarized currents\nwithin the systems. This is attributed to the recovery of half-metallicity with\nincreasing thickness. The absence of electronic states of the spin down\nelectrons around the Fermi level suppresses the contribution of this spin\nchannel to the total conductivity. This strongly influences the thermoelectric\nproperties of such systems and results in polarized thermoelectric currents.\n