Gerald Arnold

Research Interests

Prof. Arnold was active in the field of superconductivity. His research centered on the theory of the superconducting proximity effect, whereby a thin layer of otherwise non-superconducting metal is induced to become superconducting by a thick layer of superconducting metal. In addition, he has developed exact expressions for current vs. voltage characteristics of tunnel junctions involving superconductors, and for semiconducting heterostructures.

The discovery of high-temperature superconductors in 1987 prompted his interest in two-dimensional antiferromagnets, which are fundamentally different from three-dimensional antiferromagnets. Several of the high-temperature superconductors are antiferromagnetic when their oxygen content is reduced. In at least two cases, the observed antiferromagnetism is found to be very much as expected for a two-dimensional antiferromagnet. Even in the superconducting state, short-ranged antiferromagnet correlations have been observed in these materials. There are currently several theories of the mechanism of high temperature superconductivity that depend crucially upon antiferromagnetic correlations. Prof. Arnold is investigating these theories and the degree to which they may be tested by experiments such as photoemission and tunneling. The theoretical tools he employs in his research are those of finite temperature field theory, with functional integrals and Feynman diagrams providing systematic approximation methods.