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Frequency-dependent Thermal Response of the Charge System and Restricted Sum Rules in La(2-x)Sr(x)CuO(4)

M. Ortolani·P. Calvani·S. Lupi
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Abstract

By using new and previous measurements of the $ab$-plane conductivity $σ_1^{ab} (ω,T)$ of La$_{2-x}$Sr$_x$CuO$_{4}$ (LSCO) it is shown that the spectral weight $W = \int_0^Ω{σ_1^{ab} (ω,T) dω}$ obeys the same law $W = W_0 - B(Ω) T^2$ which holds for a conventional metal like gold, for $Ω$'s below the plasma frequency. However $B(Ω)$, which measures the "thermal response" of the charge system, in LSCO exhibits a peculiar behavior which points towards correlation effects. In terms of hopping models, $B(Ω)$ is directly related to an energy scale $t_T$, smaller by one order of magnitude than the full bandwidth $t_0 \sim W_0$.

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M. Ortolani, P. Calvani, S. Lupi. 2004-07-16. Frequency-dependent Thermal Response of the Charge System and Restricted Sum Rules in La(2-x)Sr(x)CuO(4). https://doi.org/10.1103/physrevlett.94.067002

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