2009/07/02 by J. Rohrkamp, J Rohrkamp, M D Phillips +5 · 10 citations
Materials Science · Physics and Astronomy · #Gapless playback #Ground state #Luttinger liquid #Magnetism in coordination complexes #Magnetostriction #Organic and Molecular Conductors Research #Phase transition #Physics of Superconductivity and Magnetism #Quantum #Quantum critical point #Quantum phase transition #Saturation (graph theory) #Thermal expansion #cond-mat.str-el
paper · pdf · doi:10.1088/1742-6596/200/1/012169
published in Journal of Physics Conference Series 200(1), 012169 (IOP Publishing) · 4 pages, 3 figures; to appear in the proceedings of the ICM 09 held in Karlsruhe, Germany
arxiv created 2009/07/02 · openalex publication_date 2010/01/01 · arxiv updated 2010/03/16 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
Compounds containing magnetic subsystems representing simple model spin systems with weak magnetic coupling constants are ideal candidates to test theoretical predictions for the generic behavior close to quantum phase transitions. We present measurements of the thermal expansion and magnetostriction of the spin-½-chain compound copper pyrazine dinitrate Cu(C 4 H 4 N 2 )(NO 3 ) 2 . Of particular interest is the low-temperature thermal expansion close to the saturation field H c ≊ 13.9 T, which defines a quantum phase transition from the gapless Luttinger liquid state to the fully saturated state with a finite excitation gap. We observe a sign change of the thermal expansion for the different ground states, and at the quantum critical point H c the low-temperature expansion approaches a divergence. Thus, our data agree very well with the expected quantum critical behaviour.