Role of disorder and strong 5$d$ electron correlation in the electronic structure of Sr2TiIrO6

Abstract

Transport and magnetic properties along with high resolution valence band photoemission study of disordered double perovskite Sr${}_2$TiIrO${}_6$ has been investigated. Insulator to insulator transition along with a magnetic transition concurrently occurs at 240 K. Comparison of valence band photoemission with band structure calculations suggests that the spin orbit coupling as well as electron correlation are necessary to capture the line shape and width of the Ir 5$d$ band. Room temperature valence band photoemission spectra show negligibly small intensity at Fermi energy, $E_F$. Fermi cut-off is observed at low temperatures employing high resolution. The spectral density of states at room temperature exhibits $|E-E_F{|}^2$ energy dependence signifying the role of electron-electron interaction. This energy dependence changes to $|E-E_F{|}^{3/2}$ below the magnetic transition evidencing the role of electron-magnon coupling in magnetically ordered state. The evolution of pseudogap ($\pm$12 meV) explains the sudden increase in resistivity ($\rho$) below 50 K in this disordered system. The temperature dependent spectral density of states at $E_F$ exhibiting $T^{1/2}$ behaviour verifies Altshuler-Aronov theory for correlated disordered systems.

References in corpus (3)

• Novel Jeff = 1/2 Mott State Induced by Relativistic Spin-Orbit Coupling in Sr2IrO4
• Critical test for Altshuler-Aronov theory: Evolution of the density of states singularity in double perovskite Sr${}_2$FeMoO${}_6$ with controlled disorder
• Calculating branching ratio and spin-orbit coupling from first-principles: A formalism and its application to iridates

Cited by in corpus (2)

• Revelation of Mott insulating state in layered honeycomb lattice Li${}_2$RuO${}_3$
• Evidence of electron correlation and weak bulk plasmon in SrMoO${}_3$