Overdoped regime of the high-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="italic">T</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant="italic">c</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>superconductor<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">HgBa</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">CuO</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn><mml:mo>+</mml:mo><mml:mi mathvariant="normal">δ</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>and the relation between normal and superconducting carrier densities

We have determined the ab-plane and c-axis components of penetration depth, ${\ensuremath{\lambda}}_{\mathit{ab}}$ and ${\ensuremath{\lambda}}_{\mathit{c}}$, and coherence length, ${\ensuremath{\xi}}_{\mathit{ab}}$ and ${\ensuremath{\xi}}_{\mathit{c}}$, for optimally doped (${\mathit{T}}_{\mathit{c}}$=96 K) and overdoped ${\mathrm{HgBa}}_{2}$${\mathrm{CuO}}_{4+\mathrm{\ensuremath{\delta}}}$ (${\mathit{T}}_{\mathit{c}}$=52 K). ${\ensuremath{\xi}}_{\mathit{ab}}$, ${\ensuremath{\xi}}_{\mathit{c}}$, and ${\ensuremath{\lambda}}_{\mathit{ab}}$ increase, whereas ${\ensuremath{\lambda}}_{\mathit{c}}$ decreases for the overdoped material in comparison to the optimally doped materials. Analysis of the data reveals that the increase of ${\ensuremath{\lambda}}_{\mathit{ab}}$ is caused by a suppression of the superconducting carrier density ${\mathit{n}}_{\mathit{s}}$, and not an enhancement of the in-plane effective mass. The decrease of ${\ensuremath{\lambda}}_{\mathit{c}}$ originates from an overcompensation in the suppression of ${\mathit{n}}_{\mathit{s}}$ by a strongly reduced effective mass along the c axis. \textcopyright{} 1996 The American Physical Society.

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