title: Symmetry breaking on the three-dimensional hyperkagome lattice of Na4Ir3O8.
abstract: We study the antiferromagnetic spin-1/2 Heisenberg model on the highly frustrated, three-dimensional, hyperkagome lattice of Na(4)Ir(3)O(8) using a series expansion method. We propose a valence bond crystal with a 72 site unit cell as a ground state that supports many, very low lying, singlet excitations. Low energy spinons and triplons are confined to emergent lower-dimensional motifs. Here, and for analogous kagome and pyrochlore states, we suggest finite temperature signatures, including an Ising transition, in the magnetic specific heat due to a multistep breaking of discrete symmetries.
authors.affiliation: Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Straße 38, D-01187 Dresden, Germany.
authors.forename: E J
authors.initials: EJ
authors.lastname: Bergholtz
authors.forename: A M
authors.initials: AM
authors.lastname: Läuchli
authors.forename: R
authors.initials: R
authors.lastname: Moessner