Interface superconductivity: History, development and prospects

Authors: Juan Pereiro, Alexander Petrovic, Christos Panagopoulos, Ivan Bozžović

Published in: Physics Express 1, 208, 2011.

The  concept  of  interface  superconductivity  was  introduced  over  50  years  ago.  Some  of  the  greatest  physicists  of that time wondered whether a quasi-two-dimensional (2D) superconductor can actually exist, what are  the  peculiarities  of  2D  superconductivity,  and  how  does  the  reduced  dimensionality  affect  the  critical temperature  (Tc).  The  discovery  of  high-temperature  superconductors,  which  are  composed  of  coupled  2D superconducting layers, further increased the interest in reduced dimensionality structures. In parallel, the advances in  experimental  techniques  made  it  possible  to  grow  epitaxial  2D  structures  with  atomically  flat  surfaces  and interfaces,  enabling  some  of  the experiments  that  were  proposed decades  ago  to  be  performed  finally.  Now  we know  that  interface  superconductivity  can  occur  at  the  junction  of  two  different  materials  (metals,  insulators, semiconductors). This phenomenon is being explored intensely; it is also exploited as a means to increase Tc  or to study quantum critical phenomena. This research may or may not produce a superconductor with a higher Tc  or a useful superconducting electronic device but it will likely bring in new insights into the physics underlying high-temperature superconductivity.