title: Similarity of the Fermi surface in the hidden order state and in the antiferromagnetic state of URu₂Si₂.
abstract: Shubnikov-de Haas measurements of high quality URu2Si2 single crystals reveal two previously unobserved Fermi surface branches in the so-called hidden order phase. Therefore, about 55% of the enhanced mass is now detected. Under pressure in the antiferromagnetic state, the Shubnikov-de Haas frequencies for magnetic fields applied along the crystalline c axis show little change compared with the zero pressure data. This implies a similar Fermi surface in both the hidden order and antiferromagnetic states, which strongly suggests that the lattice doubling in the antiferromagnetic phase due to the ordering vector Q(AF)=(001) already occurs in the hidden order. These measurements provide a good test for existing or future theories of the hidden order parameter.
authors.affiliation: INAC, SPSMS, CEA Grenoble, 38054 Grenoble, France. elena.hassinger@gmail.com
authors.forename: E
authors.initials: E
authors.lastname: Hassinger
authors.forename: G
authors.initials: G
authors.lastname: Knebel
authors.forename: T D
authors.initials: TD
authors.lastname: Matsuda
authors.forename: D
authors.initials: D
authors.lastname: Aoki
authors.forename: V
authors.initials: V
authors.lastname: Taufour
authors.forename: J
authors.initials: J
authors.lastname: Flouquet