Spacing-driven collapse of band gap and magnetic order in Sr3Ir2O7.

Using first-principles methods, we investigated the effect of structural deformation on the electronic and magnetic properties of Sr 3 Ir 2 O 7 by two tuning ways: reducing only the interlayer spacing and the uniaxial-like compression. In both cases, an insulator-metal transition is successfully achieved with significantly different Fermi surface features. The former consists of a hole pocket and an electronic pocket, while for the latter, a pseudo-gap is captured near the center of the crystallographic Brillouin zone. The anti-ferromagnetism collapses completely and is not fully synchronized with the closing of the Mott gap in two kinds of compression cases, indicating that the conventional correlation between magnetic order and Mott insulating state does not exist here. Our research is conducive to understand the nature of lattice distortion-induced electronic and magnetic transitions, and will be expected to provide a new theoretical reference for the experimental regulation of novel metallic properties in iridium. [ABSTRACT FROM AUTHOR]