2005/05/19 by P. Limelette, Patrice Limelette, V. Hardy +14 · 1 citation
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Advanced Thermoelectric Materials and Devices #Physics of Superconductivity and Magnetism #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.71.233108
published as Phys. Rev. B. 71, 233108 (2005) · 5 pages, 6 figures, accepted for publication in Physical Review B
arxiv created 2005/05/19 · openalex publication_date 2005/06/30 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
We have performed both in-plane resistivity, Hall effect, and specific heat measurements on the thermoelectric cobalt oxide Ca3Co4O9. Four distinct transport regimes are found as a function of temperature, corresponding to a low temperature insulating one up to Tmin\ensuremath≈63\phantom\rule0.3em0exK, a strongly correlated Fermi liquid up to T*\ensuremath≈140\phantom\rule0.3em0exK, with \ensuremathρ=\ensuremathρ0+AT2 and A\ensuremath≈3.63\ifmmode×\else\texttimes\fi10^\ensuremath-2\phantom\rule0.3em0ex\ensuremathμ\ensuremathΩ\phantom\rule0.2em0excm∕K2, followed by an incoherent metal with kFl\ensuremath\leqslant1 and a high temperature insulator above T**\ensuremath≈510\phantom\rule0.3em0exK. The specific heat Sommerfeld coefficient \ensuremathγ=93\phantom\rule0.3em0exmJ∕(mol\phantom\rule0.2em0exK2) confirms a rather large value of the electronic effective mass and fulfils the Kadowaki-Woods ratio A∕\ensuremathγ2\ensuremath≈0.45\ifmmode×\else\texttimes\fi10^\ensuremath-5\phantom\rule0.3em0ex\ensuremathμ\ensuremathΩ\phantom\rule0.2em0excm\phantom\rule0.2em0exK2∕(mJ2\phantom\rule0.2em0exmol^\ensuremath-2). Resistivity measurements under pressure reveal a decrease of the Fermi liquid transport coefficient A with an increase of T* as a function of pressure while the product A(T*)2∕b2 remains constant and of order h∕e2. Both thermodynamic and transport properties suggest a strong renormalization of the quasiparticles coherence scale of order T* that seems to govern also thermopower.