Inhibition of strong-coupling superconductivity by magnetic impurities: A quantum Monte Carlo study

The first exact calculation of (partialT/sub c//partialc)/sub c //sub = /0, the initial depression of the superconducting T/sub c/, due to a small concentration, c, of magnetic impurities is presented. (partialT/sub c//partialc)/sub c //sub = /0 has been calculated from the pair-breaking regime (T/sub K//T/sub co/<<1) where the impurities are magnetic, to the pair-weakening regime (T/sub K//T/sub c0/>>1). I find that (partialT/sub c//partialc)/sub c //sub = /0 can be expressed as the product of two universal functions f(λ0) and g(T/sub K//T/sub c0/), and that, in contrast to previous results, the maximum chemical bond(partialT/sub c//partialc)/sub c //sub = /0chemical bond occurs when T/sub c/0 = T/sub K/, thus resolving a long-standing experimental puzzle