title: Quantum critical 5f electrons avoid singularities in U(Ru,Rh)2Si2.
abstract: We present specific heat measurements of 4% Rh-doped URu2Si2 at magnetic fields around the proposed metamagnetic transition field H(m) approximately 34 T, revealing striking similarities to the isotructural Ce analog CeRu2Si2 for H>H(m). This suggests that strongly renormalized hybridized-band models apply equally well to both systems. The vanishing bandwidths as H-->H(m) are consistent with a quantum-critical point close to H(m). The existence of a phase transition into an ordered phase in the vicinity of H(m) for 4% Rh-doped URu2Si2, but not for CeRu2Si2, is consistent with a stronger superexchange in the case of the U 5f system. Irreversible processes at the transition indicate a strong coupling of the 5f orbitals to the lattice, most suggestive of electric quadrupolar order.
authors.affiliation: National High Magnetic Field Laboratory, Los Alamos National Laboratory, MS E536, Los Alamos, New Mexico 87545, USA.
authors.forename: A V
authors.initials: AV
authors.lastname: Silhanek
authors.forename: N
authors.initials: N
authors.lastname: Harrison
authors.forename: C D
authors.initials: CD
authors.lastname: Batista
authors.forename: M
authors.initials: M
authors.lastname: Jaime
authors.forename: A
authors.initials: A
authors.lastname: Lacerda
authors.forename: H
authors.initials: H
authors.lastname: Amitsuka
authors.forename: J A
authors.initials: JA
authors.lastname: Mydosh