Nonsymmorphic Dirac semimetal and carrier dynamics in the doped spin-orbit-coupled Mott insulator Sr2IrO4
Nonsymmorphic Dirac semimetal and carrier dynamics in the doped spin-orbit-coupled Mott insulator Sr2IrO4
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DOI：
10.1103/physrevb.102.041108
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发表时间：
2020-06
影响因子：
3.7
通讯作者：
Han Jeong Woo;Sun-Woo Kim;W. Kyung;W. Kyung;Chung-Jong Kim;G. Cao;Xiao Chen;S. Wilson;
中科院分区：
文献类型：
--
作者：
Han Jeong Woo;Sun-Woo Kim;W. Kyung;W. Kyung;Chung-Jong Kim;G. Cao;Xiao Chen;S. Wilson;
A Dirac fermion emerges as a result of interplay between symmetry and topology in condensed matter. Current research moves towards investigating the Dirac fermions in the presence of many-body effects in correlated systems. Here, we demonstrate the emergence of a correlation-induced symmetry-protected Dirac semimetal state in the lightly doped spin-orbit-coupled Mott insulator ${\mathrm{Sr}}_{2}{\mathrm{IrO}}_{4}$. We find that the nonsymmorphic crystalline symmetry stabilizes a Dirac line-node semimetal and that the correlation-induced symmetry-breaking electronic order further leads to a phase transition from the Dirac line-node to a Dirac point-node semimetal. The latter state is experimentally confirmed by angle-resolved photoemission spectroscopy and terahertz spectroscopy on ${\mathrm{Sr}}_{2}(\text{Ir},\mathrm{Tb}){\mathrm{O}}_{4}$ and ${(\text{Sr},\mathrm{La})}_{2}{\mathrm{IrO}}_{4}$. Remarkably, the electrodynamics of the massless Dirac carriers is governed by the extremely small scattering rate of about 6 ${\mathrm{cm}}^{\ensuremath{-}1}$ even at room temperature, which is iconic behavior of relativistic quasiparticles. Temperature-dependent changes in electrodynamic parameters are also consistently explained based on the Dirac point-node semimetal state.
A Dirac fermion emerges as a result of interplay between symmetry and topology in condensed matter. Current research moves towards investigating the Dirac fermions in the presence of many-body effects in correlated systems. Here, we demonstrate the emergence of a correlation-induced symmetry-protected Dirac semimetal state in the lightly doped spin-orbit-coupled Mott insulator ${\mathrm{Sr}}_{2}{\mathrm{IrO}}_{4}$. We find that the nonsymmorphic crystalline symmetry stabilizes a Dirac line-node semimetal and that the correlation-induced symmetry-breaking electronic order further leads to a phase transition from the Dirac line-node to a Dirac point-node semimetal. The latter state is experimentally confirmed by angle-resolved photoemission spectroscopy and terahertz spectroscopy on ${\mathrm{Sr}}_{2}(\text{Ir},\mathrm{Tb}){\mathrm{O}}_{4}$ and ${(\text{Sr},\mathrm{La})}_{2}{\mathrm{IrO}}_{4}$. Remarkably, the electrodynamics of the massless Dirac carriers is governed by the extremely small scattering rate of about 6 ${\mathrm{cm}}^{\ensuremath{-}1}$ even at room temperature, which is iconic behavior of relativistic quasiparticles. Temperature-dependent changes in electrodynamic parameters are also consistently explained based on the Dirac point-node semimetal state.