CsMn${}_4$As${}_3$: A layered tetragonal transition-metal pnictide compound with antiferromagnetic ground state

Abstract

We report the synthesis and properties of a new layered tetragonal ternary compound CsMn${}_4$As${}_3$ (structure: KCu${}_4$S${}_3$-type, space group: $P4/mmm$, No. 123 and $Z=2$). The material is a small band-gap semiconductor and exhibits an antiferromagnetic ground state associated with Mn spins. The compound exhibits a signature of a distinct magnetic moment canting event at 150(5)~K with a canting angle of $\approx 0.3^{\circ }$. Although, some features of the magnetic characteristics of this new compound are qualitatively similar to those of the related BaMn${}_2$As${}_2$, the underlying Mn sublattices of the two materials are quite different. While the Mn square-lattice layers in BaMn${}_2$As${}_2$ are equally spaced along the $c$-direction with the interlayer distance $d_{\mathrm{L}\mathrm{Ba}}=6.7341(4)$ Ang., the Mn sublattice forms bilayers in CsMn${}_4$As${}_3$ with the interlayer distance within a bilayer $d_{\mathrm{L}\mathrm{Cs}}=3.1661(6)$ Ang. and the distance between the two adjacent bilayers $d_{\mathrm{B}}=7.290(6)$ Ang. This difference in the Mn sublattice is bound to significantly alter the energy balance between the $J_1$, $J_2$ and $J_c$ exchange interactions within the J1-J2-Jc model compared to that in BaMn${}_2$As${}_2$ and the other related 122 compounds including the well-known iron-arsenide superconductor parent compound BaFe${}_2$As${}_2$. Owing to the novelty of its transition metal sublattice, this new addition to the family of tetragonal materials related to the iron-based superconductors brings prospects for doping and pressure studies in the search of new superconducting phases as well as other exciting correlated-electron properties.

9 pages in the published version, 8 figures

References in corpus (1)

• Itinerant ferromagnetism in the As 4$p$ conduction band of Ba${}_{0.6}$K${}_{0.4}$Mn${}_2$As${}_2$ identified by x-ray magnetic circular dichroism