[Pyeongjae Park, Younjung Jo, Je-Geun Park] Weak In-Plane Ferromagnetism and Electronic Nematicity in the Distorted Triple-Q Magnetic Phase of Co1/3TaS2 (published in Advanced Material)
Unveiling the Correlation Between Chiral Spin Texture and Electronic Nematicity in Co1/3TaS2
Co1/3TaS2 (hereafter CTS), a magnetic ion-intercalated transition metal dichalcogenide, is well known for hosting a spontaneously chiral spin texture. Due to this unique structure, it exhibits a giant Hall effect even in a state where the net magnetization is nearly zero. Recently, a few research groups discovered that an 'electronic nematicity'—referring to the directional anisotropy of charge distribution—coexists with chirality in CTS. However, it remained unclear whether this nematic phase originates from the underlying spin texture or arises from an independent mechanism.
To address this question, a joint research team measured the rotational-angle dependence of electrical resistance and torque magnetometry and subsequently performed microscopic spin-model calculations. The results revealed that the electronic nematic phase in CTS can be controlled via a subtle 'weak ferromagnetic moment' that aligns parallel to the nematic ordering direction. Notably, the distinct hysteresis loop observed in the magnetic-field-dependent torque measurements demonstrates that an external magnetic field can induce a redistribution of nematic domains, allowing this state to be written in a non-volatile manner. The microscopic spin model calculations conducted by the joint research team precisely reproduced the experimental torque hysteresis and rotational angle dependence data.
Furthermore, the research team confirmed that this weak ferromagnetic moment emerges exclusively when the underlying spin texture possesses a chiral symmetry. Consequently, through a combination of experiments and theoretical calculations, the team successfully demonstrated that the material's chiral spin structure is the direct knob for controlling the electronic nematic phase. This study establishes a crucial foundation for understanding the interactions between complex phases in symmetry-broken quantum magnets and is expected to contribute to future applications in non-volatile magnetic devices.