Dresden 2017 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 48: Spin Dynamics and Transport: Spin Excitations and Spin Torque Phenomena
MA 48.11: Vortrag
Donnerstag, 23. März 2017, 12:15–12:30, HSZ 101
Negative differential conductance in atomic-scale nano-antiferromagnets — •Steffen Rolf-Pissarczyk1,2, Shichao Yan1,2, Luigi Malavolti1,2, Jacob Burgess1,2, Gregory McMurtrie1,2, and Sebastian Loth1,2,3 — 1Max-Planck-Institut für Struktur und Dynamik der Materie, Hamburg, Germany — 2Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany — 3Institut für Funktionelle Materie und Quantentechnologien, Universität Stuttgart, Germany
Negative differential conductance (NDC) is a widely applied operation principle in modern electronic devices and it has been observed in different physical systems. The realization of a spin-based NDC effect especially in antiferromagnetic systems may enable new functionality. Here we report the manifestation of a spin-dependent NDC effect through an artificially constructed nano-antiferromagnet in the junction of a spin-polarized scanning tunneling microscope (SP-STM). The NDC occurs due to the occupation of a long-lived excited spin state of the nano-antiferromagnet which reduces the tunneling rate of the spin-polarized tunneling electrons. Applying a master rate equation method based on an effective spin-Hamiltonian provides detailed understanding of the underlying process. This NDC mechanism differs from those previously known as it uses substantially spin selection rather than energy selection in the transport channel.