The spin-1/2 Heisenberg chain: thermodynamics, quantum criticality and spin-Peierls exponents |
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| Authors: | A Klümper |
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| Institution: | Universit?t zu K?ln, Institut für Theoretische Physik, Zülpicher Strasse 77, 50937, Germany, DE
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| 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.
Received: 12 February 1998 / Received in final form: 15 March 1998 / Accepted: 17 March 1998 |
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| Keywords: | 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) |
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