OVERDOPED REGIME OF THE HIGH-T-C SUPERCONDUCTOR HGBA2CUO4+DELTA AND THE RELATION BETWEEN NORMAL AND SUPERCONDUCTING CARRIER DENSITIES

We have determined the ab-plane and c-axis components of penetration d epth, lambda(ab) and lambda(c), and coherence length, xi(ab) and xi(c) , for optimally doped (T-c=96 K) and overdoped HgBa2CuO4+delta (T-c=52 K). xi(ab), xi(c), and lambda(ab) increase, whereas lambda(c) decreas es for the overdoped material in comparison to the optimally doped mat erials. Analysis of the data reveals that the increase of lambda(ab) i s caused by a suppression of the superconducting carrier density n(s), and not an enhancement of the in-plane effective mass. The decrease o f lambda(c) originates from an overcompensation in the suppression of n(s) by a strongly reduced effective mass along the c axis.