论文标题

LANIO3膜的光学性质从压缩到拉伸应变

Optical properties of LaNiO3 films tuned from compressive to tensile strain

论文作者

Ardizzone, I., Zingl, M., Teyssier, J., Strand, H. U. R., Peil, O., Fowlie, J., Georgescu, A. B., Catalano, S., Bachar, N., Kuzmenko, A. B., Gibert, M., Triscone, J. -M., Georges, A., van der Marel, D.

论文摘要

具有较强电子相关性的材料托管了巨大的,技术上相关的 - 诸如磁性,超导性和金属绝缘体跃迁等现象。利用和控制这些效果是一个主要的挑战,在薄膜和异质结构中的晶格和应变工程中正在取得关键的进步,利用电子自由度和结构性自由度之间的复杂相互作用。在这里,我们表明LANIO3的电子结构可以通过晶格工程来调整。我们使用不同的底物在LANIO3薄膜中诱导压缩和拉伸双轴菌株。我们的测量结果揭示了光谱随应变的函数的系统变化,并且尤其是随着拉伸应变的使用,低频载体重量的增加。使用密度函数理论(DFT)计算,我们表明这种显然的反直觉效应是由于氧气八面体的方向的变化所致。计算还揭示了应变下电子结构的急剧变化,这与费米表面LifShitz的过渡有关。我们提供了一个在线小程序来探索这些效果。低于2 eV的综合光谱重量的实验值明显小于DFT结果,表明光谱重量从红外线转移到2 eV以上的能量。自由载体重量的抑制和光谱重量转移到高能量的同时表明,由于电子相关性而引起的相关带狭窄和自由载体质量增强。我们的发现为使用晶格工程的量子材料进行调整和控制提供了有希望的途径。

Materials with strong electronic correlations host remarkable -- and technologically relevant -- phenomena such as magnetism, superconductivity and metal-insulator transitions. Harnessing and controlling these effects is a major challenge, on which key advances are being made through lattice and strain engineering in thin films and heterostructures, leveraging the complex interplay between electronic and structural degrees of freedom. Here we show that the electronic structure of LaNiO3 can be tuned by means of lattice engineering. We use different substrates to induce compressive and tensile biaxial epitaxial strain in LaNiO3 thin films. Our measurements reveal systematic changes of the optical spectrum as a function of strain and, notably, an increase of the low-frequency free carrier weight as tensile strain is applied. Using density functional theory (DFT) calculations, we show that this apparently counter-intuitive effect is due to a change of orientation of the oxygen octahedra.The calculations also reveal drastic changes of the electronic structure under strain, associated with a Fermi surface Lifshitz transition. We provide an online applet to explore these effects. The experimental value of integrated spectral weight below 2 eV is significantly (up to a factor of 3) smaller than the DFT results, indicating a transfer of spectral weight from the infrared to energies above 2 eV. The suppression of the free carrier weight and the transfer of spectral weight to high energies together indicate a correlation-induced band narrowing and free carrier mass enhancement due to electronic correlations. Our findings provide a promising avenue for the tuning and control of quantum materials employing lattice engineering.

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