We report low-temperature calorimetric, magnetic and resistivity measurements on the antiferromagnetic (AF) heavy-fermion metal YbRh2Si2 (TN= 70 mK) as a function of magnetic field B. While for fields exceeding the critical value Bc0 at which TN→0 the low temperature resistivity shows an AT2 dependence, a 1/(B−Bc0) divergence of A(B) upon reducing B to Bc0 suggests singular scattering at the whole Fermi surface and a divergence of the heavy quasiparticle mass. The observations are interpreted in terms of a new type of quantum critical point separating a weakly AF ordered from a weakly polarized heavy Landau-Fermi liquid state.
@article{arxiv.cond-mat/0206289,
title = {Magnetic-Field Induced Quantum Critical Point in YbRh$_2$Si$_2$},
author = {P. Gegenwart and J. Custers and C. Geibel and K. Neumaier and T. Tayama and K. Tenya and O. Trovarelli and F. Steglich},
journal= {arXiv preprint arXiv:cond-mat/0206289},
year = {2009}
}