Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 2504.14577

Unconventional magnetism in spin-orbit coupled systems

Jian-Keng Yuan·Zhiming Pan·Congjun Wu
View original source ↗Read source document ↗Export metadata ↓

Abstract

``Unconventional magnetism" was proposed to describe the exotic states arising from Landau-Pomeranchuk instabilities in the spin channel nearly two decades ago. Its odd-partial-wave-channel (e.g. $p$-wave) states break parity giving rise to the dynamic generation of spin-orbit coupling, while its even-partial-wave-channel (e.g. $d$-wave) states break time-reversal symmetry. Both types of states can exhibit collinear and non-collinear spin configurations over Fermi surfaces with the former and latter termed as the $α$ and $β$-phases, respectively. The collinear states in even partial-wave channels are in the same symmetry class of ``altermagnetism". In this work, we investigate unconventional magnetism in both $p$- and $d$-wave channels within spin-orbit coupled systems with parity and time-reversal symmetries maintained. Based on the Ginzburg-Landau free energy analysis, the $p$-wave channel yields the gyrotropic, Rashba, Dresselhaus-type spin-orbit couplings. They compete and mix evolving from the $β$-phase to the $α$-phase with various types of spin-momentum lockings. Analyses are performed in parallel for the $d$-wave unconventional magnetism. We emphasize that the single-particle dispersion is not sufficient to justify the spin-group type symmetry of the full Hamiltonian. Furthermore, Goldstone manifolds and excitations are examined in each unconventional magnetic phase.

Explore related subjects

cond-mat.str-el

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Jian-Keng Yuan, Zhiming Pan, Congjun Wu. 2025-04-20. Unconventional magnetism in spin-orbit coupled systems. https://arxiv.org/abs/2504.14577

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Spontaneous Parity Breaking in Quantum Antiferromagnets on the Triangular Lattice

Frustration on the triangular lattice has long been a source of intriguing and often debated phases in many-body systems. Although symmetry analysis has been employed, the role of the seemingly trivial parity symmetry has received little attention. In this work, we show that phases induced by frustration are systematically shaped by an implicit rule-of-thumb associated with spontaneous parity breaking in weak longitudinal field. This principle enables us to anticipate and rationalize the regimes and conditions under which nontrivial phases emerge. For the spin-$S$ antiferromagnetic XXZ model, we demonstrate that a controversial parity-broken phase appears at intermediate values of $S$. In bilayer systems, enhanced frustration leads to additional phases, such as supersolids, whose properties can be classified by their characteristic parity features. Benefiting from our improved tensor network contraction techniques, we confirm these results through large-scale tensor-network calculations. This study offers an alternative viewpoint and a systematic approach for examining the interplay between spin, symmetry, and frustration in many-body systems.

cond-mat.str-el↗
arXiv2026

Directional Criticality and Higher-Order Flatness: Designing Van Hove Singularities in Three Dimensions

Van Hove singularities (VHSs) play a pivotal role in driving correlated electronic phenomena. Traditional classifications focus only on critical points where the band gradient vanishes in all directions. Here we establish a unified classification of VHSs in three-dimensional systems, characterized by the number of vanishing gradient components and Hessian eigenvalues: ordinary ($M$-type), higher-order ($T_1$, $T_2$, $T_3$), noncritical ordinary ($N_0$, $N_1$, $N_2$), and noncritical higher-order ($S_1$, $S_2$) types. Noncritical VHSs exhibit directional quenching: the gradient vanishes in a two-dimensional subspace while remaining finite along the orthogonal direction, yielding finite density-of-states enhancements with distinct energy dependencies. Using an $s$-orbital tight-binding model on the pyrochlore lattice with spin-orbit coupling, we demonstrate that all singularity classes emerge at distinct high-symmetry points through controlled tuning of the hopping ratio. This work establishes directional criticality and higher-order flatness as design principles for tailoring density-of-states enhancements in three-dimensional quantum materials.

cond-mat.str-el↗
arXiv2026

Quantum Rotors on the Fuzzy Sphere and the Cubic CFT

The three-dimensional cubic conformal field theory governs the critical behaviour of Heisenberg magnets with cubic anisotropy. Studying this theory non-perturbatively is challenging, because its most easily accessible observables are numerically very close to those of the more symmetric $O(3)$ model. In this work, we overcome this difficulty using the fuzzy sphere regularisation method. By adding a cubic-invariant two-body interaction to the quantum rotor Hamiltonian used for the $O(3)$ model, we break the continuous rotational symmetry by construction and unambiguously isolate the cubic critical point. Using exact diagonalisation and the density matrix renormalisation group, we calculate the scaling dimensions of several key operators, including the leading scalar singlets, and resolve the splitting of the $O(3)$ rank-two traceless symmetric tensor into the $E_g$ and $T_{2g}$ representations of the cubic group. Our results are consistent with existing Monte Carlo, conformal perturbation theory, and $\varepsilon$ expansion benchmarks, demonstrating the power of the fuzzy sphere in resolving closely spaced universality classes.

cond-mat.str-el↗