title: Repulsive Casimir effect with Chern insulators.
abstract: We theoretically predict that the Casimir force in vacuum between two Chern insulator plates can be repulsive (attractive) at long distances whenever the sign of the Chern numbers characterizing the two plates are opposite (equal). A unique feature of this system is that the sign of the force can be tuned simply by turning over one of the plates or alternatively by electrostatic doping. We calculate and take into account the full optical response of the plates and argue that such repulsion is a general phenomena for these systems as it relies on the quantized zero frequency Hall conductivity. We show that achieving repulsion is possible with thin films of Cr-doped (Bi,Sb)2Te3, that were recently discovered to be Chern insulators with quantized Hall conductivity.
authors.affiliation: Department of Physics and GISC, Loughborough University, Loughborough LE11 3TU, United Kingdom.
authors.forename: Pablo
authors.initials: P
authors.lastname: Rodriguez-Lopez
authors.affiliation: Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Strasse 38, 01187 Dresden, Germany and Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid, Spain.
authors.forename: Adolfo G
authors.initials: AG
authors.lastname: Grushin