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

Xiang Li, Xiaoting Li, Jiaqi Lin, Peng Dong, Jun Li, Mary H. Upton, Yifan Jiang, Dawei Shen, Haizhong Guo, Xuerong Liu

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$_3$.

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

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, 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 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.

Paper Structure

This paper contains 4 figures.

Figures (4)

  • Figure 1: (a) and (b): Stacking plots of RIXS spectra along $K$ and $L$ directions of PM SrIrO$_3$ and AFM SrIr$_{0.9}$Sn$_{0.1}$O$_3$. The total momentum transfer $\bm{Q}$ in the RIXS experiment is given by $\bm{Q}$=($HKL$)+$\bm{q}$, where ($HKL$) is (3 1 3), and $\bm{q}$ is the momentum shown in the figure.
  • Figure 2: Fitting of PM SrIrO$_3$ at $\bm{q}$=(0.5 0.2 0.5) (a), (0.5 0.5 0.5) (b) and (0.5 0.5 0.2) (c). The paramagnon excitations are represented with shaded blue. Other components include elastic, phonon, multi-magnon and $dd$ excitation peaks. Fittings of all RIXS spectra can be seen in supplement supplement.
  • Figure 3: Momentum dependent evolution of magnetic excitations along $K$ and $L$ directions with doping levels of $x$ = 0, 0.06 and 0.1. More doping levels were shown in supplement supplement.
  • Figure 4: (a) and (b): RIXS spectra of SrIrO$_3$ collected at 31 K and 280 K, where (a) is around AFM zone boundary at $\bm{q}$=(0.5 0.05 0.5), (b) is around AFM zone center at $\bm{q}$=(0.5 0.425 0.5). (c): Linear temperature dependence of paramagnon spectral weight at (0.5 0.425 0.5).