Regular Article

Chiral p-wave superconducting states in mesoscopic noncircular systems at zero external magnetic field

Department of Physics and Shanghai Key Laboratory of High Temperature Superconductors, Shanghai University, Shanghai 200444, P.R. China

^a e-mail: zgq_1981@shu.edu.cn

Received: 3 April 2019
Published online: 10 June 2019

Abstract

Using Bogoliubov-de Gennes formalism, the chiral order parameters in mesoscopic p-wave superconducting noncircular systems are investigated in the absence of applied magnetic field. For the perfect square or rectangular sample, a single-domain-wall state tends to emerge, accompanied by a vertical or horizontal domain wall separating the regions with different chiralities. This type of domain walls can be effectively tuned by temperature and the aspect ratio of samples, and the multi-domain-wall state containing two domain walls can be obtained. Moreover, for a p-wave square loop with a centered hole, the diagonal-symmetric mode for orders is presented, leading to four domain walls placed at the center of four arms of the loop. In particular, several peculiar domain-wall states may show up in the asymmetric square loop system with an off-centered hole.