Lafuente-Bartolome Jon, Lian Chao, Giustino Feliciano
Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX 78712.
Department of Physics, The University of Texas at Austin, Austin, TX 78712.
Proc Natl Acad Sci U S A. 2024 May 21;121(21):e2318151121. doi: 10.1073/pnas.2318151121. Epub 2024 May 17.
Halide perovskites emerged as a revolutionary family of high-quality semiconductors for solar energy harvesting and energy-efficient lighting. There is mounting evidence that the exceptional optoelectronic properties of these materials could stem from unconventional electron-phonon couplings, and it has been suggested that the formation of polarons and self-trapped excitons could be key to understanding such properties. By performing first-principles simulations across the length scales, here we show that halide perovskites harbor a uniquely rich variety of polaronic species, including small polarons, large polarons, and charge density waves, and we explain a variety of experimental observations. We find that these emergent quasiparticles support topologically nontrivial phonon fields with quantized topological charge, making them nonmagnetic analog of the helical Bloch points found in magnetic skyrmion lattices.
卤化物钙钛矿作为用于太阳能收集和节能照明的高质量半导体的一个革命性家族而出现。越来越多的证据表明，这些材料卓越的光电特性可能源于非常规的电子 - 声子耦合，并且有人提出极化子和自陷激子的形成可能是理解此类特性的关键。通过在不同长度尺度上进行第一性原理模拟，我们在此表明卤化物钙钛矿包含种类独特丰富的极化子，包括小极化子、大极化子和电荷密度波，并且我们解释了各种实验观察结果。我们发现这些涌现的准粒子支持具有量子化拓扑电荷的拓扑非平凡声子场，使它们成为在磁性斯格明子晶格中发现的螺旋布洛赫点的非磁性类似物。
