Unconventional pairing in heavy Fermion metals
- 23 Downloads
The Fermi-liquid theory of superconductivity is applicable to a broad range of systems that are candidates for unconventional pairing,e.g. heavy fermion, organic and cuprate superconductors. Ginzburg-Landau theory provides a link between the thermodynamic properties of these superconductors and Fermi-liquid theory. The multiple superconducting phases of UPt3 illustrate the role that is played by the Ginzburg-Landau theory in interpreting these novel superconductors. Fundamental differences between unconventional and conventional anisotropic superconductors are illustrated by the unique effects that impurities have on the low-temperature transport properties of unconventional superconductors. For special classes of unconventional superconductors the low-temperature transport coefficients areuniversal, i.e. independent of the impurity concentration and scattering phase shift. The existence of a universal limit depends on the symmetry of the order parameter and is achieved at low temperatures κBT ≪ γ ≪ Δ0, where γ is the bandwidth of the impurity induced Andreev bound states. In the case of UPt3 thermal conductivity measurements favor anE1g orE2u ground state. Measurements at ultra-low temperatures should distinguish different pairing states.
Unable to display preview. Download preview PDF.
- G. Volovik and L. Gor'kov, Sov. Phys. JETP Lett.39, 674 (1984).Google Scholar
- R. Heffner and M. Norman, Comm. Cond. Matt. Phys.17, 361 (1996).Google Scholar
- R. Joynt, Sup. Sci. Tech.1, 1210 (1988).Google Scholar
- M. Zhitomirskii and I. Luk'yanchuk, Sov. Phys. JETP Lett.58, 131 (1993).Google Scholar
- B. Lussier. et al., unpublished (1996).Google Scholar
- A. I. Larkin and Y. N. Ovchinnikov, inNonequilibrium Superconductivity, edited by D. Langenberg and A. Larkin (Elsevier Science Publishers, Amsterdam, 1986), pp. 493–542.Google Scholar
- D. Rainer and J. A. Sauls, inSuperconductivity: From Basic Physics to New Developments, edited by P. N. Butcher and Y. Lu (World Scientific, Singapore, 1995), pp. 45–78.Google Scholar
- L. D. Landau, Sov. Phys. JETP5, 70 (1959).Google Scholar
- G. M. Eliashberg, Zh. Eskp. Teor. Fiz.15, 1151 (1962).Google Scholar
- L. J. Buchholtz and G. Zwicknagl, Z. Phys.B23, 5788 (1981).Google Scholar
- A. Andreev, Sov. Phys. JETP19, 1228 (1964).Google Scholar