Weyl-Luttinger phase transition in pyrochlore iridates revealed by Raman scattering

Abstract

Pyrochlore iridates are thought to be a fertile ground for the realization of topologically non-trivial and strongly correlated states of matter. Here we provide a compelling evidence of interacting Weyl electrons in Nd${}_2$Ir${}_2$O${}_7$ and quadratic band touching in Pr${}_2$Ir${}_2$O${}_7$ by Raman scattering. We observe a magnetically-driven phase transition between the topological Weyl semimetal and a Luttinger semimetal with quadratic band touching in Nd${}_2$Ir${}_2$O${}_7$. Our theoretical analysis of the Raman scattering from Weyl and Luttinger quasiparticles agrees with experimental observations, and enables a characterization of the material parameters while revealing interaction and disorder effects through a relatively short quasiparticle lifetime.

8 pages, 3 figures; improved fitting of theory to experiment

References in corpus (8)

• Inelastic Light Scattering From Correlated Electrons
• Topological Mott insulator in three-dimensional systems with quadratic band touching
• Magnetic orders and topological phases from f-d exchange in pyrochlore iridates
• Electron interactions, spin-orbit coupling, intersite correlations in pyrochlore iridates
• First-principles study on cubic pyrochlore iridates Y2Ir2O7 and Pr2Ir2O7
• Role of electronic excitations in magneto-Raman spectra of graphene
• Raman response and shear viscosity in the non-Fermi liquid phase of Luttinger semimetals
• Phonon spectrum of Pr${}_2$Zr${}_2$O${}_7$ and Pr${}_2$Ir${}_2$O${}_7$ as an evidence of coupling of the lattice with electronic and magnetic degrees of freedom