$\mathcal{PT}$-symmetry as Effective Time Reversal Symmetry for Anderson Localization in a Collinear Antiferromagnet

Kim-Khuong Huynh; Takuma Ogasawara; Motoi Kimata; Sofie Søby Leiszner; Nhu-Quynh Thi Phan; Michael Anthony Quintero; Frej Søren Rattenborg; Denis Arčon; Bo Brummerstedt Iversen; Katsumi Tanigaki

arXiv · 2610.06951

$\mathcal{PT}$-symmetry as Effective Time Reversal Symmetry for Anderson Localization in a Collinear Antiferromagnet

Kim-Khuong Huynh·Takuma Ogasawara·Motoi Kimata·Sofie Søby Leiszner·Nhu-Quynh Thi Phan·Michael Anthony Quintero·Frej Søren Rattenborg·Denis Arčon·Bo Brummerstedt Iversen·Katsumi Tanigaki

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Abstract

We show that $\mathcal{PT}$-symmetry acts as the effective time-reversal symmetry governing Anderson localization in the antiferromagnet BaMn$_2$Bi$_2$, whereas the general time-reversal symmetry is broken by its long-range magnetic order. The magnetoconductance follows the laws established from breaking time-reversal symmetry throuhg the orbital coupling of charge carriers to the magnet vector potential, however, the degrees of symmetry breaking are qualitatively modulated by the magnetocrystalline anisotropy stabilizing $\mathcal{PT}$-related sublattices. The quantum interferences and hoping amplitudes governing the phenomena are drastically impaired by transverse magnetic fields, which readily cant $\mathcal{PT}$-related magnetic sublattices. Accordingly, when the $\mathcal{PT}$-related texture is weakly perturbed by longitudinal fields orienting along the sublattices, the localization is minutely affected. The robustness of the $\mathcal{PT}$-enforced degeneracies is thus governed by exchange and magnetocrystalline interactions, in contrast to the exact $\mathcal{PT}$-symmetry of the full Hamiltonian, which is broken by any finite field.

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Kim-Khuong Huynh, Takuma Ogasawara, Motoi Kimata, Sofie Søby Leiszner, Nhu-Quynh Thi Phan, Michael Anthony Quintero, Frej Søren Rattenborg, Denis Arčon, Bo Brummerstedt Iversen, Katsumi Tanigaki. 2026-10-03. $\mathcal{PT}$-symmetry as Effective Time Reversal Symmetry for Anderson Localization in a Collinear Antiferromagnet. https://arxiv.org/abs/2610.06951

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