MAGNETIC-FIELD DEPENDENCE OF THE DENSITY-OF-STATES OF YBA2CU3O6.95 ASDETERMINED FROM THE SPECIFIC-HEAT

The magnetic field dependence of the electronic density of states at t he Fermi level, N(E(F), H), is determined in single-crystal YBa2Cu3O6. 95 by specific heat measurements. The total specific heat is best desc ribed by including two predictions for the electronic specific heat of d-wave superconductivity: a T-2 term in zero field and an increased l inear term in a magnetic held applied perpendicular to the CuO2 planes . The additional linear term, which implies a finite N(E(F), H), obeys N(E(F), H) proportional to (H/H-c2)(1/2) as predicted by Volovik for superconductivity with lines of nodes in the gap.