Doping-induced redistribution of magnetic spectral weight in the substituted hexaborides Ce1−xLaxB6 and

Abstract

We investigate the doping-induced changes in the electronic structure of CeB 6 on a series of substituted Ce 1−x R x B 6 samples (R = La, Nd) using diffuse neutron scattering. We observe a redistribution of magnetic spectral weight across the Brillouin zone, which we associate with the changes in the Fermi-surface nesting properties related to the modified charge carrier concentration. In particular, a strong diffuse peak at the corner of the Brillouin zone (R point), which coincides with the propagation vector of the elusive antiferroquadrupolar (AFQ) order in CeB 6 , is rapidly suppressed by both La and Nd doping, like the AFQ order itself. The corresponding spectral weight is transferred to the X (00 1 2 ) point, ultimately stabilizing a long-range AFM order at this wave vector at the Nd-rich side of the phase diagram. At an intermediate Nd concentration, a broad diffuse peak with multiple local maxima of intensity is observed around the X point, evidencing itinerant frustration that gives rise to multiple ordered phases for which Ce 1−x Nd x B 6 is known. On the La-rich side of the phase diagram, however, dilution of the magnetic moments prevents the formation of a similar (00 1 2 )-type order despite the presence of nesting. Our results demonstrate how diffuse neutron scattering can be used to probe the nesting vectors in complex f-electron systems directly, without reference to the single-particle band structure, and emphasize the role of Fermi surface geometry in stabilizing magnetic order in rare-earth hexaborides.

RKKY Interactions of CeB6 Based on Effective Wannier Model

“…3 [20]. The present development of the ζ z and O v X-point mode appears to be related to the recent inelastic neutron scattering experiments in Ce x La 1−x B 6 [21], where the intensity q = (π, 0, 0) is enhanced and becomes dominant mode for x < 0.8.…”

An STM Perspective on Hexaborides: Surface States of the Kondo Insulator SmB6

“…Diffusive neutron scattering revealed rich phase diagrams for the two substitution series CeLa x B 6 and CeNd x B 6 . [ 145 ] Studying these phase diagrams by a highly surface sensitive technique like STM may disclose differences between the surface and the bulk.…”

“…[ 144 ] Such an additional degree of freedom can give rise to new and intriguing phases and phenomena as, for example, in the case of CeRE x B 6 . [ 145 ] It also allows for detailed substitution studies, including a change of the electron count by playing with the ratio of divalent versus trivalent elements, and enabling element‐specific measurements like electron‐spin resonance (ESR).…”

Local origin of the strong field-space anisotropy in the magnetic phase diagrams of Ce1−xLaxB6 measured in a rotating magnetic field

“…In zero magnetic field, the ground state is a arXiv:2105.10694v2 [cond-mat.str-el] 28 May 2021 double-q AFM phase III with a noncollinear spin arrangement characterized by a pair of propagation vectors, q 1 = 1 4 1 4 0 and q 2 = 1 4 1 4 1 2 ; in moderate fields (1-2 T, depending on the field direction) it changes to a single-q collinear AFM phase III [22][23][24][25][26]; and at even higher fields the order parameter of the ground state changes one more time to phase II that represents a combination of primary antiferroquadrupolar (AFQ) order with the propagation vector q AFQ = 1 2 1 2 1 2 , also referred to as orbital antiferromagnetic in earlier literature [27], and a secondary field-induced dipolar-octupolar order with the same wave vector [28][29][30][31][32][33][34][35][36]. Substitution of nonmagnetic La for Ce in the Ce 1−x La x B 6 solid solutions [21] stabilizes another multipolar phase IV, presumably antiferrooctupolar (AFO) in character [37][38][39][40][41][42][43][44][45][46][47][48].…”