SciPost Submission Page
Zeeman Quantum Geometry as a Probe of Unconventional Magnetism
by Neelanjan Chakraborti, Sudeep Kumar Ghosh, Snehasish Nandy
Submission summary
| Authors (as registered SciPost users): | Sudeep Kumar Ghosh · Snehasish Nandy |
| Submission information | |
|---|---|
| Preprint Link: | https://arxiv.org/abs/2508.14745v2 (pdf) |
| Date submitted: | Nov. 20, 2025, 12:29 p.m. |
| Submitted by: | Snehasish Nandy |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
|
| Approach: | Theoretical |
Abstract
Unconventional magnets with momentum-dependent spin-splitting but zero net magnetization form a recently identified class of collinear magnets that are challenging to probe via conventional means. We show that these systems can be distinguished through their intrinsic gyrotropic magnetic (IGM) currents, enabled by the Zeeman quantum geometry, which captures the coupled response of electronic states to momentum translation and spin rotation. Examining two prototypical two-dimensional unconventional magnets with Rashba spin-orbit coupling, a time-reversal-broken $d$-wave altermagnet and a time-reversal-symmetric $p$-wave magnet, we uncover a direct link between crystalline symmetry, spin-split band structures, and transport signatures. The $d_{x^2-y^2}$-wave altermagnet exhibits both transverse conduction and longitudinal displacement IGM currents, whereas the $p$-wave magnet supports only a transverse conduction IGM current. Remarkably, the mixed $d$-wave altermagnet supports all four types of IGM currents, including a longitudinal conduction current enabled by symmetric (Zeeman) Berry curvature that is forbidden in conventional quantum geometry. These responses, measurable via Hall transport and optical probes, persist even when conventional quantum geometry-driven linear responses vanish, offering unique access to hidden spin-split band structures. Our results establish Zeeman quantum geometry as both a diagnostic tool and a design principle for novel magnetic materials.
Author indications on fulfilling journal expectations
- Provide a novel and synergetic link between different research areas.
- Open a new pathway in an existing or a new research direction, with clear potential for multi-pronged follow-up work
- Detail a groundbreaking theoretical/experimental/computational discovery
- Present a breakthrough on a previously-identified and long-standing research stumbling block