Suppression of the tendency toward antiferromagnetic order in the Dirac semimetal SrIrO$_3$

TL;DR

This study investigates the spin dynamics of SrIrO$_3$, revealing suppressed antiferromagnetic order despite magnetic excitations similar to ordered compounds, highlighting a link between band topology and electron correlation.

Contribution

It provides new insights into how topological band structure influences magnetic excitations and order suppression in SrIrO$_3$.

Findings

Magnetic excitations in SrIrO$_3$ resemble those in Sn-substituted ordered compounds.

Pristine SrIrO$_3$ exhibits longer-lived magnetic excitations near the AFM zone center.

The results suggest a connection between band topology and electron correlation effects.

Abstract

The entangled charge and spin dynamics in strongly electron correlated system has been a fruitful playground for exploring new physical phenomena. Here with resonant inelastic X-ray scattering we studied the spin dynamics of SrIrO$_3$, a half-filled paramagnetic semimetal hosting highly itinerant Dirac Fermions due to its topological band structure. Our results show that its magnetic excitations share much similarity to the ordered compounds upon Sn substitution in exchange strength and AFM instability, while the system maintains spin non-ordered. Further, the non-ordered pristine SrIrO$_3$ hosts even longer lifetime magnetic excitations near the AFM zone center comparing to the Sn substituted ordered compounds, contrary to general expectation. These observations indicate an interesting connection between band topology and electron correlation in SrIrO$_3$.