https://doi.org/10.1007/s100510050491
The spin-1/2 Heisenberg chain: thermodynamics, quantum criticality and spin-Peierls exponents*
Universität zu Köln,
Institut für Theoretische Physik,
Zülpicher Strasse 77,
50937, Germany
Corresponding author: a kluemper@thp.uni-koeln.de
Received:
12
February
1998
Revised:
15
March
1998
Accepted:
17
March
1998
Published online: 15 October 1998
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
(
) 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)
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1998
