Nonreciprocal transport in the gate-induced strontium titanate polar superconductor
In materials science, two-dimensional electron systems (2DES) realized at the oxide surface or interface are a promising candidate to achieve novel physical properties and functionalities in a rapidly emerging quantum field. While 2-DES provides an important platform for exotic quantum events including the quantum Hall effect and superconductivity, the effect of symmetry breaking ; transition from a disorderly state in to a more definite state, on such quantum phases remain elusive. Nonreciprocal electrical transport or current-direction-dependent resistance is a probe for broken inversion symmetry (presence of a dipole), as observed on several noncentrosymmetric crystals and interfaces. In a new report, Yuki M. Itahashi and a team of scientists in applied physics, nanosystems and materials science in Japan and the U.S. reported nonreciprocal transport at the surface of a 2-D superconductor made of the superconducting material strontium titanate (SrTiO3). The team observed gigantic enhancement of the nonreciprocal region in the...