Optical absorption induced by small polaron formation in transition metal oxides: The case of Co3O4
Optical absorption induced by small polaron formation in transition metal oxides: The case of Co3O4
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DOI：
10.1103/physrevmaterials.3.102401
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发表时间：
2019-09
影响因子：
3.4
通讯作者：
T. Smart;T. Pham;Y. Ping;T. Ogitsu
中科院分区：
文献类型：
--
作者：
T. Smart;T. Pham;Y. Ping;T. Ogitsu
已知在最重要的过渡金属氧化物（TMO）中存在的小极地（SP）；然而，小极极形成的性质仍然是神秘的，并且对SPS如何影响这些材料的内在电子结构和光学特性的基本理解在很大程度上缺乏。在这项工作中，我们采用第一原理计算来调查CO $ _ {3} $ o $ $ _ {4} $中的SP组，这是多种新兴能源应用程序的高度有前途的材料，我们解决了相互矛盾的发现，即相互矛盾已经报道了系统的电子结构。我们确认CO $ _ {3} $ o $ $ _ {4} $的固有带隙为1.6 eV，我们表明孔的形成小极光片的形成显着影响了光吸收光谱，导致了0.8 ev的过渡，该evrition tur通常被误解为定义基本差距的乐队边缘。此外，我们讨论了如何利用单轴菌株来探测SP状态的Jahn-Teller扭曲，从而影响其光学转变。超越CO $ _ {3} $ o $ _ {4} $，我们的研究提出了一个通用路线图，用于建立第一原理计算方法，该方法可以同时实现SP状态，电子带结构和偏光型磁性的光学过渡的准确描述氧化物。
Small polarons (SPs) are known to exist in most important transition metal oxides (TMOs); however, the nature of small polaron formation remains enigmatic, and a fundamental understanding of how SPs impact the intrinsic electronic structure and optical properties of these materials is largely lacking. In this work, we employ first-principles calculations to investigate SP formation in Co$_{3}$O$_{4}$, a highly promising material for a wide range of emerging energy applications, and we resolve the conflicting findings that have been reported on the electronic structure of the system. We confirm that the intrinsic band gap of Co$_{3}$O$_{4}$ is 1.6 eV, and we show that the formation of hole small polarons significantly influences the optical absorption spectra, leading to a 0.8 eV transition that is often misinterpreted as the band edge that defines the fundamental gap. In addition, we discuss how uniaxial strain can be utilized to probe the Jahn-Teller distortion of SP states and in turn, effect their optical transitions. Beyond Co$_{3}$O$_{4}$, our study suggests a general roadmap for establishing a first-principles computational approach that can simultaneously achieve an accurate description of SP states, electronic band structure and optical transitions of polaronic magnetic oxides.