Guilbert Laurent, Vittadello Laura, Bazzan Marco, Mhaouech Imed, Messerschmidt Simon, Imlau Mirco
Université de Lorraine, LMOPS et CentraleSupélec, EA 4423, 2 rue E. Belin, F-57070 Metz, France.
J Phys Condens Matter. 2018 Mar 28;30(12):125701. doi: 10.1088/1361-648X/aaad34.
Charge transport due to small polarons hopping among defective (bound polarons) and regular (free polarons) sites is shown to depend in a non-trivial way on the value of the stabilization energy provided by the lattice distortion surrounding the charge carriers. This energy, normally not directly accessible for bound polarons using spectroscopic techniques, is determined here by a combination of experimental and numerical methods for the important case of small electron polarons bound to [Formula: see text] defects in the prototype ferroelectric oxide lithium niobate. Our findings provide an estimation of the [Formula: see text] polaron stabilization energy [Formula: see text] and demonstrate that in lithium niobate both free and bound polarons contribute to charge transport at room temperature, explaining the fast decay of the light-induced bound polaron population observed by transient absorption spectroscopy.
由于小极化子在缺陷（束缚极化子）和规则（自由极化子）位点之间跳跃而导致的电荷传输，被证明以一种非平凡的方式依赖于电荷载流子周围晶格畸变所提供的稳定化能量的值。对于束缚极化子，这种能量通常无法通过光谱技术直接获取，在此，对于原型铁电氧化物铌酸锂中与[公式：见文本]缺陷结合的小电子极化子这一重要情况，通过实验和数值方法相结合来确定。我们的研究结果提供了[公式：见文本]极化子稳定化能量[公式：见文本]的估计值，并表明在铌酸锂中，自由极化子和束缚极化子在室温下都对电荷传输有贡献，这解释了通过瞬态吸收光谱观察到的光致束缚极化子群体的快速衰减。
