Correlations in the low temperature specific heat across the superconducting regime of La2-xSrxCuO4 (0.05 ≤ x ≤ 0.27)

We present measurements of the low temperature specific heat (0.09K≤ T ≤ 1.5K) of seven samples of the La2−xSrxCuO4 system (0.05≤ x ≤0.27). All the data were found to fit the expression, C = A(x)T−2+α(x)Tn(x)+β(x)T3. The coefficient of the nuclear specific heat contribution A(x) was found to have a minimum value for 0.15 ≤ x ≤ 0.2, i.e. near optimum doping. The exponent of the second term n(x) was always less than unity and showed a very systematic variation with Sr-doping, having a minimum value of n ≈ 0.33 ± 0.07 for x = 0.15.