Strange semimetal dynamics in SrIrO3

Abstract

The interplay of electronic correlations, multi-orbital excitations, and spin-orbit coupling is a fertile ground for new states of matter in quantum materials. Here, we report on a polarized Raman scattering study of semimetallic SrIrO 3. The momentum-space selectivity of Raman scattering allows to circumvent the challenge to resolve the dynamics of charges with very different mobilities. The Raman responses of both holes and electrons display an electronic continuum extending far beyond the energies allowed in a regular Fermi liquid. Analyzing this response within a memory function formalism, we extract their frequency dependent scattering rate and mass enhancement, from which we determine their DC-mobilities and electrical resistivities that agree well with transport measurement. We demonstrate that its charge dynamics is well described by a marginal Fermi liquid phenomenology, with a scattering rate close to the Planckian limit. This demonstrates the potential of this approach to investigate the charge dynamics in multi-band systems.

Quantum materials with strong spin–orbit coupling: challenges and opportunities for materials chemists

“…26,27 The realisation that certain iridates and ruthenates have structures that provide a template for realising Kitaev physics has spurred intense interest in these materials over the last decade. 4,5 Electronic phases with unusual band structure topologies, such as the topological semimetal phases found in some pyrochlore iridates and in SrIrO 3 , 4,[47][48][49][50][51] are also a feature of materials with strong spin-orbit coupling. Another recent development has been the exploration of potential excitonic magnetism in d 4 .…”

Preparation of Bulk‐Phase Nitride Perovskite LaReN3 and Topotactic Reduction to LaNiO2‐Type LaReN2

“…The combination of metallic conductivity with strong spin-orbit coupling, as evidenced by the distorted ReN 6 octahedra within the triclinic I1 ¯superstructure, may give rise to unusual electronic properties as observed in the iridate perovskite SrIrO 3 . [35] LaReN 3 and LaReN 2 have temperature independent magnetic susceptibilities (Figure 4 b) that are positive at high field with values 3.4 10 À4 and 2.2 10 À4 emu mol À1 respectively at 2.2 K and 5 T, indicative of Pauli paramagnetism (Figure 4 c) in keeping with metallic properties for both compounds. This is in line with DFT predictions on LaReN 3 and for LaReN 2 the truism that nitrogen-poor transition metal nitrides are usually metallic.…”

“…A superconducting transition observed with T c =3.5 K is assigned to impurities below. The combination of metallic conductivity with strong spin‐orbit coupling, as evidenced by the distorted ReN 6 octahedra within the triclinic I superstructure, may give rise to unusual electronic properties as observed in the iridate perovskite SrIrO 3 [35] …”

Orbital dichotomy of Fermi liquid properties in Sr$_2$RuO$_4$ revealed by Raman spectroscopy

“…The presence of the FL dip in the Raman spectrum is a clear fingerprint of FL behavior, which to our knowledge has not been reported up to now. Instead, the flat Raman continua observed in correlated metals like cuprates [33], and iridates [34] have been interpreted as signaling non-FL "marginal" like behavior, with a quasiparticle scattering rate following linear rather than quadratic energy dependence. From this perspective Sr 2 RuO 4 provides an interesting model system to establish canonical FL behavior in the Raman scattering spectrum.…”