Pair correlation and dynamic Jahn-Teller effect: High-T_c in nanoclusters

¹ Lawrence Berkeley Laboratory, University of California at Berkeley - Berkeley, CA 94720 USA
² L. Landau Institute for Theoretical Physics, RAN - Moscow, 117334 Russia
³ Laboratoire de Physique des Solids, Université Paris XI, Bâtiment 510 - 91405 Orsay Cedex, France, EU

Received: 8 September 2014
Accepted: 3 November 2014

Abstract

Electronic states in metallic nanoclusters form energy shells and degree of their filling depends on the number of delocalized electrons. In the region close to half-filling the cluster's geometry oscillates between the prolate and oblate configurations (dynamic Jahn-Teller effect). For large clusters (N > 10²; N is the number of delocalized electrons) this effect competes with pair correlation and, as a result, it is perfectly realistic to observe the transition to the superconducting state. For some clusters (e.g., for Zn₇₆, Al₇₀) the value of the critical temperature is rather high .