二维约瑟夫森结阵列中的相变及噪声频谱研究

采用电阻分路(RSJ)模型，运用数值计算方法研究二维约瑟夫森结阵列的涡旋度,涡旋密度涨落随温度的变化，表明了超导阵列中存在KTB型相变.还研究了相变点附近的涡旋噪声频谱随温度、驱动电流变化的特性.计算结果与最近实验报导定性一致，并能用涡旋的运动图像来解释噪声频谱的变化规律. 关键词： 高温超导 噪声频谱 约瑟夫森结阵列 KTB相变

Phase transition and vortex noise spectrum in two-dimensional Josephson-junction array

Using the resistively shunted junction(RSJ)model,we calculate the temperature dependence of vorticities and fluctuations of vorticities in two-dimensional Josephson junction array(JJA).It is found that the phase transition is of the Berezinski-Kosterlitz-Thouless(KTB)type.We also study the temperature and driving current dependence of the noise power spectrum in the vicinity of phase transition.The calculated results are consistent with recent experimental reports,and the main characteristics of the noise power spectrum can be explained by the motion of vortices.