Electronic transport on the Shastry-Sutherland lattice in Ising-type rare-earth tetraborides

Abstract

In the presence of a magnetic field frustrated spin systems may exhibit plateaus at fractional values of saturation magnetization. Such plateau states are stabilized by classical and quantum mechanisms including order by disorder, triplon crystallization, and various competing order effects. In the case of electrically conducting systems, free electrons represent an incisive probe for the plateau states. Here we study the electrical transport of Ising-type rare-earth tetraborides RB 4 (R = Er, Tm), a metallic Shastry-Sutherland lattice showing magnetization plateaus. We find that the longitudinal and transverse resistivities reflect scattering with both the static and the dynamic plateau structure. We model these results consistently with the expected strong uniaxial anisotropy on a quantitative level, providing a framework for the study of plateau states in metallic frustrated systems.

Magnetisation process in the rare earth tetraborides, NdB4 and HoB4

“…A plateau is also observed at T = 6 K, the constant resistivity most likely arising as the system is undergoing a transition from the intermediate to the high temperature phase. This response has also been observed in ErB 4 and TmB 4 30 , where the curves can be thought of as the sum of a conventional orbital magnetoresistance with additional scattering due to magnetic ordering in the plateau state.…”

“…It would be interesting to extend in-field neutron diffraction measurements to sufficiently low temperatures to thoroughly investigate the nature of this new phase. Other R B 4 members, such as ErB 4 and TmB 4 11 , 30 show a more defined fractional magnetisation plateau and are well described by the SSL, with the proposed structures centring around antiferromagnetic and ferromagnetic stripes.…”

Topological excitations in quasi two-dimensional quantum magnets with weak interlayer interactions

“…We have carefully restricted our choice of Hamiltonian parameters to realistic ranges. We use nearly equal Heisenberg exchange interactions on the diagonal and axial bonds(J ≈ J ) as observed in the rare earth tetraborides (RB 4 , R=Er,Tm) [55,56,57]. The choice is motivated by the large magnitude of effective localized moments in these compounds which render the HP approach applicable.…”

“…1.1(a)). The rare-earth tetraborides are the material realization for frustrated SS-lattices because the antiferromagnetic Heisenberg-interactions on the dimer and axial bonds are nearly equal (J ≈ J ) [55,56,57]. Shahzad et al [58] show that for a classical spin systems in RB 4 , crystal-symmetry allowed perpendicular DMI on the axial bond gives rise to coplanar flux state (see Fig.…”

“…Since the degree of frustration can be tuned by varying the ratio of the diagonal and axial bonds, the model exhibits a wide range of novel magnetic phases [185,186,187]. The existence of a number of materials with underlying SS geometry of the magnetic ions offers the prospect of observing theoretically predicted phases and phenomena in real materials [188,55,56,57]. Since DMI is ubiquitous in all of these materials, it is natural to supplement the canonical SS model with DMI.…”