论文标题
脱离激子绝缘子候选者中的晶格和电子不稳定性TA $ _2 $ nise $ _5 $ by nonquilibrium spectroscophy
Disentangling lattice and electronic instabilities in the excitonic insulator candidate Ta$_2$NiSe$_5$ by nonequilibrium spectroscopy
论文作者
论文摘要
Ta$_2$NiSe$_5$ is an excitonic insulator candidate showing the semiconductor/semimetal-to-insulator (SI) transition below $T_{\text{c}}$ = 326 K. However, since a structural transition accompanies the SI transition, deciphering the role of electronic and lattice degrees of freedom in driving the SI transition has remained 有争议的。在这里，我们使用泵 - 探针拉曼和光致发光（PL）光谱镜调查了TA $ _2 $ nise $ _5 $中光激发的非平衡状态。晶格和电子状态的联合非平衡光谱测量结果揭示了抑制绝缘间隙的光激发亚稳态状态，但保留了低温结构失真。我们得出的结论是，电子相关性在ta $ _2 $ nise $ _5 $的SI过渡中起着至关重要的作用。
Ta$_2$NiSe$_5$ is an excitonic insulator candidate showing the semiconductor/semimetal-to-insulator (SI) transition below $T_{\text{c}}$ = 326 K. However, since a structural transition accompanies the SI transition, deciphering the role of electronic and lattice degrees of freedom in driving the SI transition has remained controversial. Here, we investigate the photoexcited nonequilibrium state in Ta$_2$NiSe$_5$ using pump-probe Raman and photoluminescence (PL) spectroscopies. The combined nonequilibrium spectroscopic measurements of the lattice and electronic states reveal the presence of a photoexcited metastable state where the insulating gap is suppressed, but the low-temperature structural distortion is preserved. We conclude that electron correlations play a vital role in the SI transition of Ta$_2$NiSe$_5$.
