Homes's law

In superconductivity, Homes's law is an empirical relation that states that a superconductor's critical temperature (T_c) is proportional to the strength of the superconducting state for temperatues well below T_c close to zero temperature(that is, the fully formed superfluid density, $\rho _{s0}$ ) multiplied by the electrical resistivity $\rho _{dc}$ measured just above the critical temperature. The relation follows the form,

$\rho _{dc}^{\alpha }\,\rho _{s0}^{\alpha }/8\simeq 4.4\,T_{c}$ .

The superscript is to recognize that may novel superconductors are anisotropic, so that the resistivity and the superfluid density are tensor quantities; the superscript $\alpha$ denotes the crystallographic direction along which these quantities are measured.

The law is named for physicist Christopher Homes and was first presented in the July 29, 2004 edition of Nature,^[1] and was the subject of a News and Views article by Jan Zaanen in the same issue^[2] in which he speculated that the high transition temperatures observed in the cuprate superconductors are due to the fact that the metallic states in these materials are as viscous as permitted by the laws of quantum physics. A more detailed version of this scaling relation subsequently appeared in Physical Review B in 2005.^[3]

Francis Pratt and Stephen Blundell have shown that Homes's law is violated in the organic superconductors. This work was first presented in Physical Review Letters in March 2005.

References

^ C. C. Homes; et al. (2004). "A universal scaling relation in high-temperature superconductors". Nature (London). 430: 539–541. doi:10.1038/nature02673. {{cite journal}}: Explicit use of et al. in: |author= (help)
^ J. Zaanen (2004). "Superconductivity: Why the temperature is high". Nature (London). 430: 512–513. doi:10.1038/430512a.
^ C. C. Homes, S. V. Dordevic, T. Valla and M. Strongin (2005). "Scaling of the superfluid density in high-temperature superconductors". Phys. Rev. B. 72: 134517. doi:10.1103/PhysRevB.72.134517.{{cite journal}}: CS1 maint: multiple names: authors list (link)

[1] C. C. Homes; et al. (2004). "A universal scaling relation in high-temperature superconductors". Nature (London). 430: 539–541. doi:10.1038/nature02673. {{cite journal}}: Explicit use of et al. in: |author= (help)

[2] J. Zaanen (2004). "Superconductivity: Why the temperature is high". Nature (London). 430: 512–513. doi:10.1038/430512a.

[3] C. C. Homes, S. V. Dordevic, T. Valla and M. Strongin (2005). "Scaling of the superfluid density in high-temperature superconductors". Phys. Rev. B. 72: 134517. doi:10.1103/PhysRevB.72.134517.{{cite journal}}: CS1 maint: multiple names: authors list (link)

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See also

References