Phase transition in bulk single crystals and thin films of VO2 by nano-infrared spectroscopy and imaging

Mengkun Liu; Aaron J. Sternbach; Martin Wagner; Tetiana V. Slusar; Tai Kong; Sergey L. Bud'ko; Salinporn Kittiwatanakul; M. M. Qazilbash; Alexander McLeod; Zhe Fei; Elsa Abreu; Jingdi Zhang; Michael Goldflam; Siyuan Dai; Guang-Xin Ni; Jiwei Lu; Hans A. Bechtel; Michael C. Martin; Markus B. Raschke; Richard D. Averitt; Stuart A. Wolf; Hyun-Tak Kim; Paul C. Canfield; D. N. Basov

arXiv · 1506.04786

Phase transition in bulk single crystals and thin films of VO2 by nano-infrared spectroscopy and imaging

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Abstract

We have systematically studied a variety of vanadium dioxide (VO2) crystalline forms, including bulk single crystals and oriented thin films, using infrared (IR) near-field spectroscopic imaging techniques. By measuring the IR spectroscopic responses of electrons and phonons in VO2 with sub-grain-size spatial resolution (~20 nm), we show that epitaxial strain in VO2 thin films not only triggers spontaneous local phase separations but also leads to intermediate electronic and lattice states that are intrinsically different from those found in bulk. Generalized rules of strain and symmetry dependent mesoscopic phase inhomogeneity are also discussed. These results set the stage for a comprehensive understanding of complex energy landscapes that may not be readily determined by macroscopic approaches.

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Mengkun Liu, Aaron J. Sternbach, Martin Wagner, Tetiana V. Slusar, Tai Kong, Sergey L. Bud'ko, Salinporn Kittiwatanakul, M. M. Qazilbash, Alexander McLeod, Zhe Fei, Elsa Abreu, Jingdi Zhang, Michael Goldflam, Siyuan Dai, Guang-Xin Ni, Jiwei Lu, Hans A. Bechtel, Michael C. Martin, Markus B. Raschke, Richard D. Averitt, Stuart A. Wolf, Hyun-Tak Kim, Paul C. Canfield, D. N. Basov. 2015-06-15. Phase transition in bulk single crystals and thin films of VO2 by nano-infrared spectroscopy and imaging. https://arxiv.org/abs/1506.04786

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