[Paper Review] Electrical Regulation of Transverse Spin Currents in Unconventional Magnetic Ferroeletrics

Yudi Yang, Zhuang Qian+5 more|arXiv (Cornell University)|Jan 4, 2026

Multiferroics and related materials0 citations

TL;DR

Demonstrates that hexagonal YMnO3 hosts a beta-phase unconventional magnetism with intrinsic spin-momentum locking, enabling a transverse pure spin current driven by an electric field without SOC, and proposes a nonvolatile spintronic transistor controlled by ferroelectric domain walls.

ABSTRACT

We identify hexagonal YMnO$_3$ as a material realization of the elusive $β$-phase of unconventional magnetism, a noncollinear, noncoplanar antiferromagnetic state defined by intrinsic spin-momentum locking and a topological spin texture. First-principle calculations reveal that this unique electronic structure enables a perpendicular electric field to generate a transverse pure spin current, a response that occurs without requiring relativistic spin-orbit coupling. Symmetry analysis demonstrates that this spin current is intimately related to the material's ferroelectric polarization that breaks the inversion symmetry and is rigorously forbidden at domain walls where electrical polarization vanishes. This provides a blueprint for a non-volatile transistor where a gate voltage switches the spin current conductivity by controlling domain wall density, enabling all-electrical control for energy-efficient antiferromagnetic spintronics.

Motivation & Objective

• Identify a material realization of the beta-phase of unconventional magnetism in a real compound.
• Elucidate how ferroelectric polarization enables spin-current generation without relying on relativistic SOC.
• Develop a symmetry-based framework linking spin currents to spin-group symmetries and ferroelectric order.
• Show how domain walls control spin-current conductivity for all-electrical, nonvolatile device concepts.

Proposed method

• Perform first-principles calculations (DFT) with calibrated Hubbard U to reproduce noncollinear, noncoplanar antiferromagnetic ground state in YMnO3.
• Analyze spin-group symmetries to derive spin-current response tensors for polar and nonpolar phases.
• Compute spin-current conductivity tensors using Kubo formalism with tight-binding models from Wannier90, separating TS-even and TS-odd contributions.
• Map spin-current response to ferroelectric polarization and domain-wall configurations to predict controllable on/off behavior.
• Propose a nonvolatile transistor design where ferroelectric domain walls modulate spin-current generation in a YMnO3 channel.

Experimental results

Research questions

• RQ1 Can YMnO3 realize the beta-phase unconventional magnetism with intrinsic spin-momentum locking?
• RQ2 How does ferroelectric polarization enable spin-current generation in the absence of spin–orbit coupling?
• RQ3 What is the relationship between spin-current conductivity and ferroelectric/domain-wall states in YMnO3?
• RQ4 Can domain-wall engineering provide all-electrical, nonvolatile control of spin transport in an antiferromagnetic system?
• RQ5 How do spin-group symmetries constrain the form of spin-current response tensors in polar vs nonpolar phases?

Key findings

• YMnO3 in the beta-phase exhibits noncollinear, noncoplanar AFM order with a momentum-space spin texture of winding number w=2.
• An electric field along the c-axis drives a transverse pure spin current with spin polarization locked to current direction, without requiring SOC.
• The spin-current response has both T-even and T-odd components, with T-odd dominating in State I and essential for transport behavior.
• Spin-current conductivity is strictly forbidden in the nonpolar phase, establishing a strong coupling between ferroelectric polarization and spin transport.
• A critical U value (Uc ≈ 5.2 eV) separates insulating beta-phase from metallic alpha-phase, while the beta-phase band gap remains robust around ~1.55 eV across a wide U range.
• Ferroelectric domain walls (P=0) suppress spin-current generation, enabling an all-electrical, nonvolatile transistor concept where domain-wall density gates spin transport.