D-wave superconductivity

Ichimura K, Takami M, Nomura K (2008) Direct observation of d-wave superconducting gap in /c-(BEDT-TTP)2Cu[N(CN)2]Br with scanning tunneling microscopy. J Phys Soc Jpn 77 114707/1-6... 

Figure 2. The imaginary part of the spin susceptibility at Q in the d-wave superconducting (a,b) and normal (c,d) states. Curves show the results of our calculations...

The chosen variational wavefunction is the d-wave superconducting wave-function with projection to remove double occupation ... 

Chubukov A.V., Pines D., and Schmatian J., (2003). A Spin Fluctuation Model for d-wave Superconductivity in The Physics of Conventional and Unconventional Superconductors eds. by Bennemann K.H. and Ketterson J.B., Vol. 1 (Springer-Verlag). 

In this work we apply anisotropic Glnzburg-Landau (GL) theory [22], previously extended by us to include coupled s-wave and d-wave superconducting order parameters [23], to qualitatively analyze the single-crystal and oriented-film data on the 214- and 123-materials. In particular we think that the large.Sommerfeld coefficients 7 - S mJ/mol [4,24,25] and 9 mj/mol [18,20] for the 40 K and 90 K... 

To illustrate this behaviour we briefly discuss an example which may be relevant to CeCu2 Si2. Qualitatively the complex phase diagram of CeCu2Si2 can be described by a simple mean-field model for a conventional spin density wave ground state (competing with d-wave superconductivity within a two band model proposed by Dahm (2001)). The calculated phase diagram displayed in fig. 8 shows that a state with dxy symmetry can become stable within the SDW phase. This is in contrast to the pairing states with d 2 yi symmetry considered by Kato... 

The reported superconducting gap spectra have been analyzed in the fiamework of d-wave superconductivity. It has been found that results can be, in principle, described in terms of the d-wave order parameter. 

The e-p interactions, taken as responsible for electron pairing, driving transition into a superconducting state for classical low-Tc superconductors, have almost been abandoned and considered inappropriate to high-Tc cuprates [see e.g. 10]. Some aspects of d - wave superconductivity can be described by strongly correlated electron models e.g. Hubbard - like or t - J models (e.g. [9,13-16]), even without explicit e-p interactions. The underlying leitmotiv in electron correlation treatments... 

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