title: Thermodynamics of the spin Luttinger liquid in a model ladder material.
abstract: The phase diagram in temperature and magnetic field of the metal-organic, two-leg, spin-ladder compound (C5H12N)2CuBr4 is studied by measurements of the specific heat and the magnetocaloric effect. We demonstrate the presence of an extended spin Luttinger-liquid phase between two field-induced quantum critical points and over a broad range of temperature. Based on an ideal spin-ladder Hamiltonian, comprehensive numerical modeling of the ladder specific heat yields excellent quantitative agreement with the experimental data across the entire phase diagram.
authors.affiliation: London Centre for Nanotechnology, University College London, London WC1E 6BT, United Kingdom.
authors.forename: Ch
authors.initials: Ch
authors.lastname: Rüegg
authors.forename: K
authors.initials: K
authors.lastname: Kiefer
authors.forename: B
authors.initials: B
authors.lastname: Thielemann
authors.forename: D F
authors.initials: DF
authors.lastname: McMorrow
authors.forename: V
authors.initials: V
authors.lastname: Zapf
authors.forename: B
authors.initials: B
authors.lastname: Normand
authors.forename: M B
authors.initials: MB
authors.lastname: Zvonarev
authors.forename: P
authors.initials: P
authors.lastname: Bouillot
authors.forename: C
authors.initials: C
authors.lastname: Kollath
authors.forename: T
authors.initials: T
authors.lastname: Giamarchi
authors.forename: S
authors.initials: S
authors.lastname: Capponi
authors.forename: D
authors.initials: D
authors.lastname: Poilblanc
authors.forename: D
authors.initials: D
authors.lastname: Biner
authors.forename: K W
authors.initials: KW
authors.lastname: Krämer