Dresden 2011 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 22: CE: Low-dimensional Systems - Materials 2
TT 22.6: Vortrag
Dienstag, 15. März 2011, 12:00–12:15, HSZ 304
Spin-spin correlation of the spin-1/2 Heisenberg-chain compound CuPzN measured by magnetostriction — •Jens Rohrkamp1, Markus Garst2, Matt D. Phillips3, Mark M. Turnbull3, and Thomas Lorenz1 — 1II. Physikalisches Institut, Universität zu Köln, Germany — 2Institut für theoretische Physik, Universität zu Köln, Germany — 3Carlson School of Chemistry and Biochemistry, Clark University, USA
The spin-1/2 Heisenberg chain is one of the rare examples of quantum-spin Hamiltonians, which can be solved analytically exact. An experimental realization of this Hamiltonian is found in copper pyrazine dinitrate Cu(C4H4N2)(NO3)2 (or CuPzN). The weak coupling constant J ≈ 10 K in this compound leads to a critical magnetic field of about 14 T, which is accessible in typical superconducting laboratory magnets. At this field the system undergoes a quantum phase transition from the gapless Luttinger-liquid state to the fully saturated state with a finite excitation gap. As recently shown in [1] the field- and temperature-induced length changes are proportional to the spin-spin correlation function <SiSj>. We present high-resolution measurements of thermal expansion and magnetostriction and compare these to calculations performed via Bethe ansatz.
[1] Anfuso et al. PRB 77, 235113 (2008)
This work was supported by the DFG through SFB 608.