ISSN:
1573-7357
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract A weak-coupling theory of the itinerant-electron antiferromagnet forT〉T c is described, Vertex and self-energy parts are treated self-consistently using Ward-Pitaevskii identities. The weak-coupling criterion is that the scalar three-vertex must be suitably small. This condition is not satisfied right down toT c ; however, it is satisfied in a region nearT c where the corrections to the bare electron-electron interaction are not small. Expressions are derived for the specific heat, temperature derivative of the electrical resistivity, etc., which are all proportional to the weakly singular form[T c /(T−T c )] n , withh«1. An analogous theory applies for superconductors. In this case the weak-coupling exponenth is approximately equal to(T c /E F )2. This quantity is typically 10−8–10−7 for superconductors, and in the weak-coupling temperature regime the lambda curve singularity would not be observable experimentally. However, for an itinerant-electron antiferromagnet such as chromium, the quasicubic shape of the electron and hole Fermi surfaces causes enhancement ofh to a value of order 10−1. For chromium the theory is consistent with experimental results and with a recent theory by Dzyaloshinskii and Kats (using a different method).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00656544
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