Magnetic Induction of d + i d Order in High-Tc Superconductors

TL;DR

This paper proposes that a magnetic induction of a d + i d superconducting order parameter explains recent experimental observations in high-Tc superconductor Bi2Sr2CaCu2O8, involving symmetry breaking and boundary currents.

Contribution

It introduces a novel d + i d order parameter phase transition mechanism that accounts for observed magnetic moments and energy gap features in high-Tc superconductors.

Findings

Development of a small d-xy order parameter with pi/2 phase shift.

Explanation of magnetic moments via boundary currents.

Consistency with recent experimental data.

Abstract

I propose that the phase transition in Bi2Sr2CaCu2O8 recently observed by by Krishana et al [Science 277, 83 (1997)] is the development of a small d-xy superconducting order parameter phased by pi/2 with respect to the principal d-(x2-y2) one to produce a minimum energy gap delta. The violation of both parity and time-reversal symmetry allows the development of a magnetic moment, the key to explaining the experiment. The origin of this moment is a quantized boundary current of I = 2 e delta / h at zero temperature.