Browsing by Author "Bradby, JE"

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    Understanding the unusual response to high pressure in KBe2BO3F2
    (Springer Nature, 2017-06-22) Yu, DH; Avdeev, M; Sun, DH; Huston, LQ; Shiell, TB; Sun, QB; Lu, T; Gu, QF; Liu, H; Bradby, JE; Yie, N; Liu, Y; Wang, JY; McIntyre, GJ
    Strong anisotropic compression with pressure on the remarkable non-linear optical material KBe2BO3F2 has been observed with the linear compression coefficient along the c axis found to be about 40 times larger than that along the a axis. An unusual non-monotonic pressure response was observed for the a lattice parameter. The derived bulk modulus of 31 ± 1 GPa indicates that KBe2BO3F2 is a very soft oxide material yet with stable structure up to 45 GPa. A combination of high-pressure synchrotron powder X-ray diffraction, high-pressure Raman spectroscopy, and Density Functional Theory calculations points to the mechanism for the unusual pressure response being due to the competition between the K-F bond length and K-F-K bond angle and the coupling between the stretching and twisting vibration modes. This article is licensed under a Creative Commons Attribution 4.0 International License.