论文标题
通过光导率观察到的TA2Nise 5中激素绝缘体状态的压力抑制
Pressure suppression of the excitonic insulator state in Ta2NiSe5 observed by optical conductivity
论文作者
论文摘要
层状硫化硫化硫酸盐Ta2nise5最近引起了人们对长期寻求激子绝缘子（EI）的强大候选者的兴趣。由于预期EI的物理特性敏感地依赖于外部压力，因此重要的是要阐明TA2Nise5中微观电子状态的压力演化。在这里，我们报告了在高压至10 GPA下测量的TA2NISE5的光导率[s（w）]，低温和低温为8 k。在环境压力下冷却时，S（W）在文献中已经报道了，在环境压力下冷却约为0.17 eV，在0.38 eV处形成了一个明显的激发峰峰值。压力增加后，能量差距变窄，并扩大了激子峰。在PS〜3 GPA处的结构跃迁之上，能量隙被部分填充，表明TA2Nise5是在EI状态被压力抑制后的半学。在较高的压力下，S（W）表现出没有能量间隙的金属特性。提出了S（W）的详细压力演化，并主要根据与压力相关性的弱化而讨论。
The layered chalcogenide Ta2NiSe5 has recently attracted much interest as a strong candidate for the long sought excitonic insulator (EI). Since the physical properties of an EI are expected to depend sensitively on the external pressure, it is important to clarify the pressure evolution of microscopic electronic state in Ta2NiSe5. Here we report the optical conductivity [s(w)] of Ta2NiSe5 measured at high pressures to 10 GPa and at low temperatures to 8 K. With cooling at ambient pressure, s(w) develops an energy gap of about 0.17 eV and a pronounced excitonic peak at 0.38 eV, as already reported in the literature. Upon increasing pressure, the energy gap becomes narrower and the excitonic peak is broadened. Above a structural transition at Ps~3 GPa, the energy gap becomes partially filled, indicating that Ta2NiSe5 is a semimetal after the EI state is suppressed by pressure. At higher pressures, s(w) exhibits metallic characteristics with no energy gap. The detailed pressure evolution of s(w) is presented, and discussed mainly in terms of a weakening of excitonic correlation with pressure.
