First-principles study of magnetic states and the anomalous Hall conductivity of $M$Nb$_3$S$_6$ ($M$=Co, Fe, Mn, and Ni)

Abstract

Inspired by the observation of the extremely large anomalous Hall effect in the absence of applied magnetic fields or uniform magnetization in CoNb3S6 [Nature Comm. 9, 3280 (2018), Phys. Rev. Research 2, 023051 (2020)], we perform first-principles study of this and related compounds of the M Nb3S6 type with different transition metal M ions to determine their magnetic orders and the anomalous Hall conductivity (AHC). We find that non-coplanar antiferromagnetic ordering is favored relative to collinear or coplanar order in the case of M =Co, Fe and Ni, while ferromagnetic ordering is favored in MnNb3S6 at low temperatures. The AHC in these materials with non-coplanar spin ordering can reach about e 2 /h per crystalline layer, while being negligible for coplanar and collinear cases. We also find that the AHC depends sensitively on doping and reaches a maximum for intermediate values of the local spin exchange potential between 0.3 and 0.8 eV. Our AHC results are consistent with the reported Hall measurements in CoNb3S6 and suggest a possibility of similarly large anomalous Hall effects in related compounds.

Visualizing the out-of-plane electronic dispersions in an intercalated transition metal dichalcogenide

“…1(a) with high symmetry points marked. Notably, the observed hexagonal symmetry from ARPES data doesn't agree with the expected rectangular surface Brillouin zone from a collinear AFM state [24] [25]. Therefore, we see no signature of the electronic reconstruction in the AFM state.…”

Electric Ferro-Axial Moment as Nanometric Rotator and Source of Longitudinal Spin Current

“…The conditions for active Q, M , and T in solids are presented on the basis of group theory [5][6][7][8][9][10][11][12][13][14][15]. Such a symmetry classification has unveiled potentially ferroic materials even without the net dipole moments, such as the (non)collinear antiferromagnet Mn 3 Sn, α-Mn, and CoX 3 S 6 (X = Nb and Ta) showing the giant anomalous Hall effect [16][17][18][19][20][21][22][23][24][25][26][27].…”