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 at (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,

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

The law is named for physicist Christopher Homes and was first presented in the July 29, 2004 edition of Nature, and was the subject of a News and Views article by Jan Zaanen in the same issue 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.

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.

See also

• Uemura's law
• Tanner's law