Non-hermiticity in spintronics: oscillation death in coupled spintronic nano-oscillators through emerging exceptional points

TL;DR

This paper demonstrates the experimental observation of exceptional points in coupled spintronic nano-oscillators at room temperature, revealing complex dynamics and amplitude death, and proposes their potential for ultrasensitive sensors and neuromorphic computing.

Contribution

It provides the first experimental demonstration of exceptional points in spintronic nano-oscillators and develops a linearized non-Hermitian model to describe their dynamics.

Findings

Observation of amplitude death in coupled spintronic oscillators

Development of a non-Hermitian model matching experimental data

Potential applications in ultrasensitive sensors and neuromorphic hardware

Abstract

The emergence of exceptional points (EPs) in the parameter space of a non-hermitian (2D) eigenvalue problem is studied in a general sense in mathematical physics, and has in the last decade successively reached the scope of experiments. In coupled systems, it gives rise to unique physical phenomena, which enable novel approaches for the development of seminal types of highly sensitive sensors. Here, we demonstrate at room temperature the emergence of EPs in coupled spintronic nanoscale oscillators and hence exploit the system's non-hermiticity. We describe the observation of amplitude death of self-oscillations and other complex dynamics, and develop a linearized non-hermitian model of the coupled spintronic system, which properly describes the main experimental features. Interestingly, these spintronic nanoscale oscillators are deployment-ready in different applicational technologies, such as field, current or rotation sensors, radiofrequeny and wireless devices and, more recently, novel neuromorphic hardware solutions. Their unique and versatile properties, notably their large nonlinear behavior, open up unprecedented perspectives in experiments as well as in theory on the physics of exceptional points. Furthermore, the exploitation of EPs in spintronics devises a new paradigm for ultrasensitive nanoscale sensors and the implementation of complex dynamics in the framework of non-conventional computing.