Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Material-specific gap function in the high-temperature superconductors   We present theoretical arguments and experimental support for the idea that
high-Tc superconductivity can occur with s-wave, d-wave, or mixed-wave pairing
in the context of a magnetic mechanism. The size and shape of the gap is
different for different materials. The theoretical arguments are based on the
t-J model as derived from the Hubbard model so that it necessarily includes
three-site terms. We argue that this should be the basic minimal model for
high-Tc systems. We analyze this model starting with the dilute limit which can
be solved exactly, passing then to the Cooper problem which is numerically
tractable, then ending with a mean field approach. It is found that the
relative stability of s-wave and d-wave depends on the size and the shape of
the Fermi surface. We identify three striking trends. First, materials with
large next-nearest-neighbor hopping (such as YBa(2)Cu(3)O(7-x)) are nearly pure
d-wave, whereas nearest-neighbor materials (such as La(2-x)Sr(x)CuO(4)) tend to
be more s-wave-like. Second, low hole doping materials tend to be pure d-wave,
but high hole doping leads to s-wave. Finally, the optimum hole doping level
increases as the next-nearest-neighbor hopping increases. We examine the
experimental evidence and find support for this idea that gap function in the
high-temperature superconductors is material-specific.

16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math
9
The categories of this paper are: nlin
21
The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an