paper

Composition dependence of bulk properties in the Co-intercalated transition-metal dichalcogenide Co $_{1/3}$ TaS $_{2}$

arXiv:2401.10421 · doi:10.1103/PhysRevB.109.L060403

Abstract

Spontaneous Hall conductivity has recently been reported in the triangular lattice antiferromagnet Co $_{1/3}$ TaS $_{2}$ under a zero magnetic field. This phenomenon originates from the distinctive noncoplanar triple-Q magnetic ground state, possessing uniform real-space Berry curvature characterized by scalar spin chirality. We investigated the physical properties of Co $_{1/3}$ TaS $_{2}$ by judiciously controlling the composition, revealing a drastic change in its bulk properties, even by slight variations in cobalt composition, despite the same crystal structure. For $0.299 < x < 0.325$ , Co $_{x}$ TaS $_{2}$ keeps all the characteristics of the ground state consistent with the previous studies -- two antiferromagnetic phase transitions at $T_{N 1}$ and $T_{N 2} (< T_{N 1})$ , a large spontaneous Hall conductivity ( $I ¨ _{x y} (H = 0)$ ), and a weak ferromagnetic moment along the c-axis. However, samples with $x > 0.330$ exhibit distinct bulk properties, including the absence of both $I ¨ _{x y} (H = 0)$ and the weak ferromagnetic moment. Our neutron diffraction data reveal that Co $_{x}$ TaS $_{2}$ with $x > 0.330$ develops coplanar helical magnetic order with $q_{m 1} = (1/3, 0, 0)$ . This is entirely different from what has been seen in $x < 0.325$ , explaining the observed composition dependence.

15 pages, 4 figures, accepted for publication in Phys. Rev. B

Composition dependence of bulk properties in the Co-intercalated transition-metal dichalcogenide Co1/3​TaS2​

Abstract

Composition dependence of bulk properties in the Co-intercalated transition-metal dichalcogenide Co $_{1/3}$ TaS $_{2}$