高温超导体的电子比热研究

ELECTRONIC SPECIFIC HEAT IN HIGH-T_c SUPERCONDUCTORS 

在vanHove奇异性背景下,从BardeenGooperSchrieffer超导理论和二维紧束缚能带结构出发,推导了各向异性的d波序参量方程和d波的电子比热公式,并研究了在临界温度Tc处的电子比热跃变和低温下电子比热的温度行为及掺杂关系.得出了考虑到vanHove奇异性可以提高Tc处的比热跃变以及d波低温电子比热与温度的平方成线性关系的结论.

Although the mechanism of high\| T c oxide superconductors is not clear until now, the density of states (DOS) of quasiparticle contains van Hove singularity (VHS) and the symmetry of d\|wave pairing are proved by many experiments. In this paper, by using the equation of anisotropic order parameter and the formula of DOS from two\|dimensional tight\|binding band structure under the model of VHS, we study the specific heat jump at \%T\%\-c and the temperature behaviors of electronic specific heat at low temperatures. We came to two conclusions. One is that the electronic specific heat exhibits a square\|temperature dependence at very low temperature, the other is that the specific heat jump is enhanced by considering VHS at \%T\%\-c.