Berlin 2008 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 34: Correlated Electrons: Metal-Insulator Transition 2
TT 34.9: Talk
Thursday, February 28, 2008, 16:15–16:30, H 2053
Dynamic scaling at MIT in yttrium hydride switchable mirrors — •A. V. Pronin1, I. G. Romijn2, H. B. Brom2, A. F. Th. Hoekstra2, and J. Wosnitza1 — 1Hochfeld-Magnetlabor Dresden (HLD), FZD, 01314 Dresden, Germany — 2Kamerlingh Onnes Laboratory, Leiden University, 2300 RA Leiden, The Netherlands
Yttrium hydride demonstrates a remarkable transition of its electronic and optical properties upon change of hydrogen concentration: a thin YHx film can be continuously and reversibly brought from a shiny metal at x = 2 to a transparent dielectric at x = 3, by changing pressure of the surrounding hydrogen gas [1]. It has been showed that the metal-insulator transition (MIT) could be neatly passed under constant hydrogen pressure by changing the carrier doping via ultraviolet illumination at low temperatures [2]. Pronounced electron-electron interactions are posited to lead to the opening of a large optical gap. The established scaling laws of the conductivity with temperature and doping [2] are strong indications for the quantum nature of the metal-insulator transition in YHx. To shed more light on the quantum nature of the MIT, the frequency dependence of conductivity is very informative. In an extensive frequency range, frequency ω and temperature T will influence the conductivity in a similar way, which will lead to a so-called ω/T-scaling behaviour. In this talk results on the optical conductivity in the sub-terahertz regime will be presented.
[1] J. N. Huiberts, et al., Nature (London) 380, 231 (1996).
[2] A. F. Th. Hoekstra, et al., Phys. Rev. Lett. 86, 5349 (2001).