Ground-state magnetic structures of topological kagome metals RV_{6}Sn_{6} (R=Tb,Dy,Ho,Er)

Abstract

Magnetic kagome metals have attracted tremendous research interests recently, because they represent an ideal playground for exploring the fascinating interplay between their intrinsically inherited topologically nontrivial electron band structures, magnetism and electronic correlation effects, and the resultant novel electronic/magnetic states and emergent excitations. In this work, we report a comprehensive single-crystal neutron diffraction investigation of the ground-state magnetic structures of the recently discovered V-based topological kagome metals RV_{6}Sn_{6} (R = Tb, Dy, Ho, Er). Furthermore, the sample synthesis details and our systematic studies of crystal structure, low-temperature magnetic and thermodynamic properties of these compounds via various in-house characterization techniques are also reported. Our single-crystal neutron diffraction measurements confirm that the long-range magnetic order forms below 4.3 K for R=Tb, 3.0 K for R=Dy, 2.4 K for R=Ho, and 0.6 K for R=Er, respectively. The ground-state magnetic structures of the studied compounds are comprehensively determined via the magnetic crystallography approaches. It can be revealed that RV_{6}Sn_{6} (R = Tb, Dy, Ho) have a collinear ferromagnetic order in the ground state, with the ordered magnetic moment aligned along the c axis for R = Tb, Ho, while approximately 20^{∘} tilted off from the c axis for R = Dy. In contrast, ErV_{6}Sn_{6} shows an A-type antiferromagnetic structure with a magnetic propagation vector k = (0, 0, 0.5), and with the ordered magnetic moment aligned in the ab plane. The ordered magnetic moments are determined as 9.4(2) µ_{B}, 6.6(2) µ_{B}, 6.4(2) µ_{B}, and 6.1(2) µ_{B} for R = Tb, Dy, Ho, and Er, respectively. A comparison of the low-temperature magnetic structures for both the extensively investigated topological kagome metal series of RV_{6}Sn_{6} and RMn_{6}Sn_{6} is given in detail. This allows to gain new insights into the complex magnetic interactions, diverse single-ion magnetic anisotropies and spin dynamics in these compounds. The reported ground-state magnetic structures in RV_{6}Sn_{6} (R = Tb, Dy, Ho, Er) can pave the way for further explorations of the possible interplay between magnetism and topologically nontrivial electron band structures in the magnetically ordered phase regime.