【摘要】 基于Nozières-Schmitt-Rink(NSR)理论的强耦合系统,研究了高温超导体从电子预配对的形成到玻色-爱因斯坦凝聚的演变过程.首次利用NSR理论,在临界温度以上的温度区域,计算了电子熵、电子比热容等热力学量及线性比热系数,并相应地描绘出了各物理量随温度的变化曲线.由比热系数随温度的变化曲线可知,在大于临界温度时比热系数已随温度的减小而减小.这就意味着,在NSR理论框架下,强耦合系统中有赝隙现象产生.通过比热系数的变化趋势确定赝隙的存在是这篇文章得到的重要结果.更多还原

【Abstract】 Based on the strong coupling systems in the Nozieres-Schmitt-Rink theory,the evolving process from BCS state to Bose-Einstein condensation state is discussed,the electronic entropy,specific heat and specific heat coefficient at the level above the critical superconducting temper(T_C) ature are evaluated,and the various physical quantities as functions of temperature are demonstrated.The fact that the specific heat coefficient lowers with decreasing temperature(above) the critical superconducting temperature reveals the pseudo-gap in strong coupling systems.It is concluded that the electronic specific heat coefficient serves as the important factor to verify the existence of pseudo-gap.更多还原