N\'eel vector controlled exceptional contours in $p$-wave magnet-ferromagnet junctions

TL;DR

This paper explores how the orientation of the Neel vector in p-wave magnet-ferromagnet interfaces can be used to control non-Hermitian degeneracies, such as exceptional lines and rings, offering a new platform for tunable topological features.

Contribution

It introduces a novel mechanism for realizing and controlling exceptional contours in non-Hermitian systems using p-wave magnetic interfaces with odd parity.

Findings

Exceptional lines and rings can be tuned via Neel vector orientation.

Symmetry analysis explains the origin of these exceptional contours.

Phase rigidity characterizes the non-Hermitian degeneracies.

Abstract

Non-Hermitian systems can host exceptional degeneracies where not only the eigenvalues, but also the corresponding eigenvectors coalesce. Recently, $p$-wave magnets have been introduced, which are characterized by their unusual odd parity. In this work, we propose the emergence of non-Hermitian degeneracies at the interface of $p$-wave magnets and ferromagnets. We demonstrate that this setup offers a remarkable tunability allowing realization of exceptional lines and rings, which can be controlled via the orientation of the $p$-wave N\'eel vector. We present the origin of these exceptional contours based on symmetry, and characterize them using phase rigidity. Our works puts forward a versatile platform to realize controllable non-Hermitian degeneracies at odd parity magnetic interfaces.