Rojas-Gatjens Esteban, Silva-Acuña Carlos, Kandada Ajay Ram Srimath
School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, Georgia 30332, USA.
School of Physics, Georgia Institute of Technology, 837 State Street, Atlanta, Georgia 30332, USA.
Mater Horiz. 2022 Jan 4;9(1):492-499. doi: 10.1039/d1mh01010g.
The anharmonicity of the Ruddlesden Popper metal-halide lattice, and its consequences for their electronic and optical properties, are paramount in their basic semiconductor physics. It is thus critical to identify specific anharmonic optical phonons that govern their photophysics. Here, we address the nature of phonon-phonon scattering probabilities of the resonantly excited optical phonons that dress the electronic transitions in these materials. Based on the temperature dependence of the coherent phonon lifetimes, we isolate the dominant anharmonic phonon and quantify its phonon-phonon interaction strength. Intriguingly, we also observe that the anharmonicity is distinct for different phonons, with a few select modes exhibiting temperature-independent coherence lifetimes, indicating their predominantly harmonic nature. However, the population and dephasing dynamics of excitons are dominated by the anharmonic phonon.
鲁德尔斯登-波珀金属卤化物晶格的非谐性及其对其电子和光学性质的影响，在其基础半导体物理学中至关重要。因此，识别控制其光物理过程的特定非谐光学声子至关重要。在这里，我们研究了这些材料中修饰电子跃迁的共振激发光学声子的声子-声子散射概率的性质。基于相干声子寿命的温度依赖性，我们分离出主导的非谐声子并量化其声子-声子相互作用强度。有趣的是，我们还观察到不同声子的非谐性是不同的，少数选定模式表现出与温度无关的相干寿命，表明它们主要是谐性的。然而，激子的布居和退相动力学由非谐声子主导。
