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Full-Text Articles in Condensed Matter Physics
Non-Hermitian Topology Of One-Dimensional Spin-Torque Oscillator Arrays, Benedetta Flebus, Rembert A. Duine, Hilary M. Hurst
Non-Hermitian Topology Of One-Dimensional Spin-Torque Oscillator Arrays, Benedetta Flebus, Rembert A. Duine, Hilary M. Hurst
Faculty Research, Scholarly, and Creative Activity
Magnetic systems have been extensively studied both from a fundamental physics perspective and as building blocks for a variety of applications. Their topological properties, in particular those of excitations, remain relatively unexplored due to their inherently dissipative nature. The recent introduction of non-Hermitian topological classifications opens up new opportunities for engineering topological phases in dissipative systems. Here, we propose a magnonic realization of a non-Hermitian topological system. A crucial ingredient of our proposal is the injection of spin current into the magnetic system, which alters and can even change the sign of terms describing dissipation. We show that the magnetic …
Electron-Induced Massive Dynamics Of Magnetic Domain Walls, Hilary M. Hurst, Victor Galitski, Tero T. Heikkilä
Electron-Induced Massive Dynamics Of Magnetic Domain Walls, Hilary M. Hurst, Victor Galitski, Tero T. Heikkilä
Faculty Research, Scholarly, and Creative Activity
We study the dynamics of domain walls (DWs) in a metallic, ferromagnetic nanowire. We develop a Keldysh collective coordinate technique to describe the effect of conduction electrons on rigid magnetic structures. The effective Lagrangian and Langevin equations of motion for a DW are derived. The DW dynamics is described by two collective degrees of freedom: position and tilt-angle. The coupled Langevin equations therefore involve two correlated noise sources, leading to a generalized fluctuation-dissipation theorem (FDT). The DW response kernel due to electrons contains two parts: one related to dissipation via FDT, and another `inertial' part. We prove that the latter …