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arXiv · 2205.04492

Frustrated Magnetic Cycloidal Structure and Emergent Potts Nematicity in CaMn$_2$P$_2$

Farhan Islam·Thaís V. Trevisan·Thomas Heitmann·Santanu Pakhira·Simon X. M. Riberolles·N. S. Sangeetha·David C. Johnston·Peter P. Orth·David Vaknin
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Abstract

We report neutron-diffraction results on single-crystal CaMn$_2$P$_2$ containing corrugated Mn honeycomb layers and determine its ground-state magnetic structure. The diffraction patterns consist of prominent (1/6, 1/6, $L$) reciprocal lattice unit (r.l.u.; $L$ = integer) magnetic Bragg reflections, whose temperature-dependent intensities are consistent with a first-order antiferromagnetic phase transition at the N\'eel temperature $T_{\rm N} = 70(1)$ K. Our analysis of the diffraction patterns reveals an in-plane $6\times6$ magnetic unit cell with ordered spins that in the principal-axis directions rotate by 60-degree steps between nearest neighbors on each sublattice that forms the honeycomb structure, consistent with the $P_Ac$ magnetic space group. We find that a few other magnetic subgroup symmetries ($P_A2/c$, $P_C2/m$, $P_S\bar{1}, P_C2, P_Cm, P_S1$) of the paramagnetic $P\bar{3}m11^\prime$ crystal symmetry are consistent with the observed diffraction pattern. We relate our findings to frustrated $J_1$-$J_2$-$J_3$ Heisenberg honeycomb antiferromagnets with single-ion anisotropy and the emergence of Potts nematicity

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Farhan Islam, Thaís V. Trevisan, Thomas Heitmann, Santanu Pakhira, Simon X. M. Riberolles, N. S. Sangeetha, David C. Johnston, Peter P. Orth, David Vaknin. 2022-05-09. Frustrated Magnetic Cycloidal Structure and Emergent Potts Nematicity in CaMn$_2$P$_2$. https://doi.org/10.1103/physrevb.107.054425

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