Springer LINK: The European Physical Journal B - Abstract Volume 5 Issue 3 (1998) pp 677-685

The European Physical Journal B

ISSN: 1434-6028 (printed version)
ISSN: 1434-6036 (electronic version)

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Abstract Volume 5 Issue 3 (1998) pp 677-685

The spin-1/2 Heisenberg chain: thermodynamics, quantum criticality and spin-Peierls exponents

A. Klümper (a)

Universität zu Köln, Institut für Theoretische Physik, Zülpicher Strasse 77, 50937, Germany

Received: 12 February 1998 / Received in final form: 15 March 1998 / Accepted: 17 March 1998

Abstract: We present numerical and analytical results for the thermodynamical properties of the spin-1/2 Heisenberg chain at arbitrary external magnetic field. Special emphasis is placed on logarithmic corrections in the susceptibility and specific heat at very low temperatures (T/J=10^-24) and small fields. A longstanding controversy about the specific heat is resolved. At zero temperature the spin-Peierls exponent is calculated in dependence on the external magnetic field. This describes the energy response of the system to commensurate and incommensurate modulations of the lattice. The exponent for the spin gap in the incommensurate phase is given.

PACS. 75.10.Jm Quantized spin models- 75.40.-s Critical-point effects, specific heats, short-range order- 72.15.Nj Collective modes (e.g., in one-dimensional conductors)

(a) email: kluemper@thp.uni-koeln.de

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