Hefei National Laboratory for Physical Sciences at the Microscale, CAS Center for Excellence in Nanoscience, and CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei, Anhui 230026, China.
School of Physics, Nankai University, Tianjin 300071, China.
Nat Commun. 2017 Jun 14;8:15561. doi: 10.1038/ncomms15561.
In correlated systems, intermediate states usually appear transiently across phase transitions even at the femtosecond scale. It therefore remains an open question how to determine these intermediate states-a critical issue for understanding the origin of their correlated behaviour. Here we report a surface coordination route to successfully stabilize and directly image an intermediate state in the metal-insulator transition of vanadium dioxide. As a prototype metal-insulator transition material, we capture an unusual metal-like monoclinic phase at room temperature that has long been predicted. Coordinate bonding of L-ascorbic acid molecules with vanadium dioxide nanobeams induces charge-carrier density reorganization and stabilizes metallic monoclinic vanadium dioxide, unravelling orbital-selective Mott correlation for gap opening of the vanadium dioxide metal-insulator transition. Our study contributes to completing phase-evolution pathways in the metal-insulator transition process, and we anticipate that coordination chemistry may be a powerful tool for engineering properties of low-dimensional correlated solids.
在相关系统中，即使在飞秒尺度上，中间态通常也会在相变过程中短暂出现。因此，如何确定这些中间态仍然是一个悬而未决的问题，这是理解其相关行为起源的关键问题。在这里，我们报告了一种表面配位途径，成功地稳定和直接观察到二氧化钒金属-绝缘转变中的中间态。作为原型金属-绝缘转变材料，我们在室温下捕获到了一种长期以来一直预测的不寻常的类金属单斜相。L-抗坏血酸分子与二氧化钒纳米梁的配位键合诱导载流子密度重新排列，并稳定了金属性单斜二氧化钒，揭示了二氧化钒金属-绝缘转变的轨道选择性莫特相关作用以打开能隙。我们的研究有助于完成金属-绝缘转变过程中的相演变途径，我们预计配位化学可能是工程低维相关固体性质的有力工具。
