title: Heat capacity reveals the physics of a frustrated spin tube.
abstract: We report on theoretical and experimental results concerning the low-temperature specific heat of the frustrated spin-tube material [(CuCl(2)tachH(3)Cl]Cl(2) (tach denotes 1,3,5-triaminocyclohexane). This substance turns out to be an unusually perfect spin-tube system which allows to study the physics of quasi-one-dimensional antiferromagnetic structures in rather general terms. An analysis of the specific-heat data demonstrates that at low enough temperatures the system exhibits a Tomonaga-Luttinger liquid behavior corresponding to an effective spin-3/2 antiferromagnetic Heisenberg chain with short-range exchange interactions. On the other hand, around 2 K the composite spin structure of the chain is revealed through a Schottky-type peak in the specific heat. We argue that the dominating contribution to the peak originates from gapped magnon-type excitations related to the internal degrees of freedom of the rung spins.
authors.affiliation: Institute of Solid State Physics, Bulgarian Academy of Sciences, Tzarigradsko chaussee 72, 1784 Sofia, Bulgaria. Nedko.Ivanov@Physik.Uni-Magdeburg.DE
authors.forename: Nedko B
authors.initials: NB
authors.lastname: Ivanov
authors.forename: Jürgen
authors.initials: J
authors.lastname: Schnack
authors.forename: Roman
authors.initials: R
authors.lastname: Schnalle
authors.forename: Johannes
authors.initials: J
authors.lastname: Richter
authors.forename: Paul
authors.initials: P
authors.lastname: Kögerler
authors.forename: Graham N
authors.initials: GN
authors.lastname: Newton
authors.forename: Leroy
authors.initials: L
authors.lastname: Cronin
authors.forename: Yugo
authors.initials: Y
authors.lastname: Oshima
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nojiri