Dresden 2014 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 40: Transport: Spintronics and magnetotransport (organized by TT)

HL 40.2: Vortrag

Dienstag, 1. April 2014, 09:45–10:00, BEY 81

Tuning the ballistic anisotropic magnetoresistance in single-atom contacts via the apex atom — •Fabian Otte¹, Yuriy Mokrousov², and Stefan Heinze¹ — ¹Instiut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität zu Kiel, D-24098 Kiel, Germany — ²Peter Grünberg Institut and Institue for Advanced Simulation, Forschungszentrum Jülich und JARA, D-52425 Jülich, Germany

Recently, the tunneling anisotropic magnetoresistance has been demonstrated at the single-atom limit using scanning tunneling spectroscopy and was explained based on density functional theory calculations of the anisotropy of the vacuum local density of states (LDOS) [1]. In the contact regime the explanation via the LDOS breaks down due to overlap of the wave functions and therefore actual calculations of the conductance are necessary. Here, we report first-principles calculations of ballistic transport in model systems of such single-atom contacts using our recently developed Wannierfunction based approach [2]. We present the ballistic anisotropic magnetoresistance (BAMR) in contact and tunneling regime between two ferromagnetic Ni monowires terminated by single 4d- and 5d- transition metal apex atoms. We show that the BAMR in the tunneling regime can be enhanced by up to an order of magnitude from 20% for Ni- to 150% for 5d-apex atoms. We also observe a change of sign in the BAMR between tunneling and contact regime.
N. Néel et al., PRL 110, 037202 (2013)
B. Hardrat et al., PRB 85, 245412 (2012)