https://doi.org/10.1007/s100510070159
Pressure dependence and non-universal effects of microscopic couplings on the spin-Peierls transition in CuGeO3
Institut für Theoretische Physik, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
Received:
3
September
1999
Revised:
7
February
2000
Published online: 15 September 2000
The theory by Cross and Fisher (CF) is by now commonly accepted
for the description of the spin-Peierls transition within an
adiabatic approach,
involving however a continuum approximation for the relevant
response function. Using density matrix renormalization group
(DMRG) techniques we are able to treat the spin system
on the lattice exactly up to numerical inaccuracies. Thus we
find the correct dependence of the equation of state on the
spin-spin interaction constant
which in the CF theory drops out completely. With respect to 
we focus on the pressure dependence of the critical temperature
and analyze the ratio of the spectral gap and the transition
temperature.
PACS: 75.10.Jm – Quantized spin models / 75.50.Ee – Antiferromagnetics / 75.40.Cx – Static properties (order parameter, static susceptibility, heat capacities, critical exponents, etc.)
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000
