强烈相关的电子系统的颜色理论
Swagata Acharya1,2, Dimitar Pashov3, Cedric Weber4
1Institute for Molecules and Materials, Radboud University, Nijmegen, 6525 AJ, The Netherlands. swagata.acharya@nrel.gov.
Nature communications
|September 9, 2023
概括
强烈相关的绝缘体由于子间隙刺激子而呈现颜色. 不同的ab initio理论解释了NiO的绿色,但需要动态平均场理论 (DMFT) 来解释MnF2的粉红色调,揭示了激子形成和光学亮度因素.
科学领域:
- 凝聚物质物理学 凝聚物质物理学
- 材料科学 材料科学 材料科学
- 计算化学计算化学
背景情况:
- 强烈相关的过渡金属绝缘器经常显示颜色,尽管有很大的带间隙.
- 解释这种颜色需要理论方法来解释晶体中的子间隙激子.
- 从光学亮度区分激子形成至关重要,但具有挑战性.
研究的目的:
- 为了研究NiO (绿色) 和MnF2 (粉红色) 中的颜色的起源,使用ab initio多体格林的函数理论.
- 为了区分解释激子形成与光学亮度的理论要求.
- 确定导致这些材料可见光吸收的关键因素.
主要方法:
- 对NiO和MnF2应用基于扰动性GW近似理论.
- 使用动态平均场理论 (DMFT) 来捕捉复杂的电子相关性.
- 激子属性的分析,包括它们的形成和光学转换概率.
主要成果:
- 扰动性GW方法成功地解释了NiO的绿色.
- 同样的GW方法无法解释MnF2的粉红色.
- 通过DMFT捕获的高阶旋转翻转过渡对于MnF2的颜色至关重要.
- 对称性降低会影响激发的亮度,但不会影响它们的基本存在.
结论:
- 需要不同的理论框架才能充分理解相关绝缘体的颜色.
- 激发形成可以通过GW近似来解释,而光学亮度可能涉及更复杂的相关性 (DMFT).
- 旋转翻转转换在像MnF2.2这样的材料的光学特性中起着重要作用.
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