抄録
Excess conductivity due to fluctuations above the superconducting transition temperature Tc in two-dimensional systems is studied both theoretically and experimentally. Theoretically a small correction term added to the Maki-Thompson (MT) term is proposed. This correction term becomes not less important at relatively high temperatures. Experimental results on thallium films are as follows: (1) In the zero electric field limit excess conductivity is well described as the sum of the Aslamazov-Larkin (AL) and MT terms when T is close to Tc. However at relatively high temperatures, η\gtrsim0.1 (η=ln(T⁄Tc)), the contribution from the above-mentioned correction term is observed. (2) An empirical relation between the pair-breaking parameter δ and RNsq was found to be δ=δ0+const×RNsq. (3) When η is small excess conductivity in finite electric field is well expressed as the sum of the nonlinear AL and MT terms. (4) The characteristic electric field is observed to be proportional to η3⁄2.
