近日，德国马克斯·普朗克固体研究所的Eva Benckiser及其研究团队取得一项新进展。经过不懈努力，他们发现印迹原子位移驱动钒酸钙钛矿中的自旋轨道序。相关研究成果已于2024年10月29日在国际知名学术期刊《自然—物理学》上发表。
本研究表明，通过在相同同构衬底的不同晶面上沉积外延薄膜，可以在反铁磁莫特绝缘体YVO3中实现原子位移的方向性印记。所选的这些晶面使得包括与覆盖层之间的晶格和极性失配在内的其他已知控制参数几乎保持不变。研究人员观察到交错轨道序和磁序的特征，并展示了不同晶面上独特的自旋-轨道序排列模式。
研究人员将这些结果归因于衬底晶面所印记的特定八面体旋转和阳离子位移模式对YVO3中键的共价性和超交换相互作用的影响。这项研究结果表明，衬底诱导的晶格畸变模式模板化是超越传统应变工程策略的材料设计新途径。
据悉，钙钛矿材料（一般组成为ABO3）展现出极为丰富的量子态，包括轨道序、磁性以及超导性。其灵活且相对简单的结构使得不同化合物能够直接进行化学替代，并在原子尺度上形成清晰的cube-on-cube组合的外延异质结构。钙钛矿的许多不同物理性质是由其相对于理想立方钙钛矿结构的微小偏离所决定的，而这些偏离的控制极具挑战性。
附：英文原文
Title: Imprinted atomic displacements drive spin–orbital order in a vanadate perovskite
Author: Radhakrishnan, Padma, Rabinovich, Ksenia S., Boris, Alexander V., Frsich, Katrin, Minola, Matteo, Christiani, Georg, Logvenov, Gennady, Keimer, Bernhard, Benckiser, Eva
Issue&Volume: 2024-10-29
Abstract: Perovskites with the generic composition ABO3 exhibit an enormous variety of quantum states, such as orbital order, magnetism and superconductivity. Their flexible and comparatively simple structure allows for straightforward chemical substitution and cube-on-cube combination of different compounds in atomically sharp epitaxial heterostructures. Many of the diverse physical properties of perovskites are determined by small deviations from the ideal cubic perovskite structure, which are challenging to control. Here we show that directional imprinting of atomic displacements in the antiferromagnetic Mott insulator YVO3 can be achieved by depositing epitaxial films on different facets of the same isostructural substrate. These facets were chosen such that other well-known control parameters, including lattice and polarity mismatch with the overlayer, remain nearly unchanged. We observe signatures of staggered orbital and magnetic order and demonstrate distinct spin–orbital ordering patterns on different facets. We attribute these results to the influence of specific octahedral rotation and cation displacement patterns, which are imprinted by the substrate facet, on the covalency of the bonds and the superexchange interactions in YVO3. Our results show that substrate-induced templating of lattice distortion patterns constitutes a pathway for materials design beyond established strain-engineering strategies.
DOI: 10.1038/s41567-024-02686-8
Source: https://www.nature.com/articles/s41567-024-02686-8