Phenomenological Theory of a Scalar Electronic Order: Application to Skutterudite PrFe₄P₁₂

Abstract

By phenomenological Landau analysis, it is shown that a scalar order parameter with the pointgroup symmetry Γ 1g explains most properties associated with the phase transition in PrFe 4 P 12 at 6.5 K. The scalar-order model reproduces magnetic and elastic properties in PrFe 4 P 12 consistently such as (i) the anomaly of the magnetic susceptibility and elastic constant at the transition temperature, (ii) anisotropy of the magnetic susceptibility in the presence of uniaxial pressure, and (iii) the anomaly in the elastic constant in magnetic field. An Ehrenfest relation is derived which relates the anomaly of the magnetic susceptibility to that of the elastic constant at the transition.

Multipole Orders and Fluctuations in Strongly Correlated Electron Systems

“…If such scalars are aligned with unequal amplitudes, the alternating component arises in CEF splitting. 59,60,120,151) The lattice should be distorted accordingly, but without breaking the point-group symmetry. In PrRu 4 P 12 , not only the distortion has been observed by X-ray and polarized neutron diffraction, 47) but also the alternation of CEF splitting has been observed by inelastic neutron scattering (INS).…”

“…Furthermore, the behavior of the elastic constants under a finite magnetic field can also be understood in terms of the scalar order scenario. 60) Recently, C 11 was also measured under hydrostatic pressure.…”

NMR Study of Filled Skutterudite Pr0.9Ce0.1Ru4P12

“…In spite of the magnetic ground state for the half of Pr sites, no indication of magnetic ordering has been observed down to 60 mK [3]. The M-I transition has been ascribed theoretically to an antiferro-hexadecapole order or scalar order of 4f electrons based on a strong c-f hybridization without breaking the local symmetry at the Pr site [4,5]. Recently, the effect of Ce substitution on PrRu 4 P 12 has been studied [6], and it shows that the M-I transition markedly shifts to lower temperature caused by a small amount of Ce substitution.…”

Anomalous properties in the low-carrier ordered phase ofPrRu4P12: Consequence of hybridization between conduction andPr Saha1, Sugawara2, Namiki3 et al. 2009Phys. Rev. B210110View full textAdd to dashboardCite

“…20,21 Recently, the M-I transition has been ascribed theoretically to an antiferro-hexadecapole order or scalar order without breaking the local symmetry at the Pr-site. 22,23 However, a recent photoemission study claims that there is no notable change in c-f hybridization strength across the M-I transition. 24 We have succeeded in growing high-quality single crystals of PrRu 4 P 12 and its reference compound LaRu 4 P 12 , which has no 4f -electron.…”