Field-dependent specific-heat of the pure and diluted 4f electron system Yb4As3

The experimental field-dependent specific heat of the polydomain pure Yb4As3 and diluted (Yb1−xLux)4As3 (x = 0.01, 0.03) systems is presented and compared with that calculated by the numerical quantum transfer-matrix method. The simulations have been performed using the S = 1/2 antiferromagnetic Heisenberg model with the transverse staggered field (appearing as a result of the antisymmetric Dzyaloshinskii–Moriya interaction) and a uniform magnetic field perpendicular to the staggered field. In the model calculations the fixed microscopic parameters have been taken and the impurity distribution has been considered. A significant improvement with respect to the previous results is shown.