Magnetic-excitation-assisted photoluminescence from self-trapped exciton states in MnO
Magnetic-excitation-assisted photoluminescence from self-trapped exciton states in MnO
复制标题
MnO 中自俘获激子态的磁激发辅助光致发光
DOI：
10.1088/0953-8984/28/1/016004
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
T. Nagashima and T. Suemoto
中科院分区：
文献类型：
--
作者：
J. Nishitani;T. Nagashima and T. Suemoto
我们研究了MnO单晶的光致发光，观察到了一个新的强发射带，其高能边在20K以下为1.905 eV，在20~30K和40K以上分别为1.875 eV和1.815 eV。在不同的临界温度下，各发光带强度随温度的变化呈阶梯式递减，表明发射光谱由三个独立的激发态组成。用声子和磁子与三种自陷激子(STE)态耦合的方式解释了发光光谱中发射边带的精细结构。基于实验中观察到的斯托克斯位移和由光致发光强度与温度的关系估计的热激活能，我们提出了STE态的组态坐标图，并从三种STE态解释了磁激发辅助光致发光过程中辐射和非辐射弛豫的机制。
We examined the photoluminescence (PL) in single-crystal MnO (111) and observed a new strong emission band with a high-energy-side edge of 1.905 eV below 20 K. The emission bands with high-energy-side edges of 1.875 eV and 1.815 eV were also observed between 20 K and 30 K, and above 40 K, respectively. The temperature dependence of the intensity of each PL band showed step-like decreases at different critical temperatures, which suggests that the emission spectrum consist of contributions from three independent excited states. The fine structures of emission sidebands in the PL spectrum were interpreted in terms of phonons and magnons coupled with three types of self-trapped exciton (STE) states. Based on the Stokes shifts observed in our experiments and the thermal activation energies estimated from the temperature dependence of the PL intensity, we propose a configuration coordinate diagram for STE states and explain the mechanism of radiative and nonradiative relaxations in the magnetic-excitation-assisted PL process from the three types of STE states.