https://doi.org/10.1007/s100510050953
Orbital effect of a magnetic field on two-leg Hubbard ladder
1
Laboratoire de Physique de la Matière Condensée,
Département de Physique,
Faculté des Sciences de Tunis,
Campus universitaire, 1060 Tunis, Tunisia
2
Laboratoire de Physique des Solides (associé au CNRS) ,
Université de Paris-Sud, 91405 Orsay Cedex, France
Received:
5
May
1999
Published online: 15 October 1999
We study the effect of a magnetic field on the dimensional
crossover of weakly coupled two-leg Hubbard ladders under
pressure. Our model is based on the perturbative renormalization
approach (PRG)
with two cut-off parameters, the bandwidth E0 and a
characteristic magnetic energy .
We determine the temperature-pressure phase diagram for different values of the magnetic field and discuss the relative
stability of the d-wave superconducting phase (SCd) and the two dimensional Fermi liquid phase (2D) which appear at zero field.
We show that the field induces a reduction in the effective dimensionality of the system and confines the electron motion
within the ladder. In fact, we find that with increasing magnetic field, the isolated ladder phase gets wider at the expense
of the SCd phase which disappears at a critical magnetic field Hc. The superconducting transition temperature Tc
is found to decrease as the field increases up to Hc for which Tc falls to zero.
Concerning the 2D phase, we show that it is destroyed for
greater than the crossover temperature at which the
system crosses to 2D phase at zero magnetic field.
PACS: 64.60.-i – General studies of phase transitions / 64.60.Ak – Renormalization-group, fractal, and percolation studies of phase transitions / 71.27.+a – Strongly correlated electron systems; heavy fermions
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999