Superfluidity and phase separation in helium films
Superfluidity and phase separation in helium films
复制标题
氦膜中的超流动性和相分离
DOI：
10.1103/physrevb.19.2488
复制
发表时间：
1979
影响因子：
3.7
通讯作者：
D. Nelson
中科院分区：
文献类型：
--
作者：
A. Berker;D. Nelson
提出了Blume-Emery-Griffiths模型的矢量概括，以描述/sup 3/he-/sup 4/he混合物中的膜中的超流量，并通过与散装混合物相比，通过近似的恢复反应方案来解决。超级流体过渡线通过临界终点连接到相分开曲线。 3/HE浓度X在X <或x = 0.12处发生。有效的三临界相图是在有效的三级限制点附近的一定限制中获得的处理还描述了二维液体相位分离的纯 /sup 4 /he膜特定的热量高于超流体过渡温度，对应于涡旋对的等级分离，而温度升高。«较少
A vectorial generalization of the Blume-Emery-Griffiths model is proposed to describe superfluidity in films of /sup 3/He-/sup 4/He mixtures, and is solved by an approximate renormalization scheme due to Migdal. In contrast to bulk mixtures, the line of superfluid transitions is connected to the phase-separation curve by a critical end point. The universal jump of the superfluid density, present in the pure /sup 4/He system, is preserved with increasing /sup 3/He concentration x until the critical end point occurs at x < or approx. = 0.12. At smaller x, phase separation causes a kink in the superfluid density versus temperature curve. No tricritical point occurs for any value of the model parameters, although an effectively tricritical phase diagram is obtained in a certain limit. Lines of constant superfluid density bunch up near the effective tricritical point, as predicted by tricritical scaling theory. This treatment also describes superfluidity in pure /sup 4/He films in the presence of two-dimensional liquid-gas phase separation. In addition we calculate the specific heat of the pure /sup 4/He system, using the recursion relations of Kosterlitz. This specific heat has a broad maximum above the superfluid transition temperature, corresponding to a gradual dissociation of vortex pairs withmore » increasing temperature.« less