Dresden 2006 – scientific programme

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HL: Halbleiterphysik

HL 50: Poster II

HL 50.1: Poster

Thursday, March 30, 2006, 16:30–19:00, P3

Pressure-Induced Insulator-Metal Transition in (CoC10H10)0.25TiSe2 — •Sergey Ovsyannikov^1,2, Vladimir Shchennikov², Alexander Titov³, and Yoshiya Uwatoko¹ — ¹The Institute for Solid State Physics, The University of Tokyo, Kashiwanoha, 5-1-5, Kashiwa, Chiba 277-8581, JAPAN — ²High-Pressure Group, Institute of Metal Physics, Urals Division of Russian Academy of Sciences, GSP-170, 18 S. Kovalevskaya Str., Yekaterinburg 620041,RUSSIA — ³Institute of Metal Physics, Urals Division of Russian Academy of Sciences, GSP-170, 18 S. Kovalevskaya Str., Yekaterinburg 620219, RUSSIA

In the present work we (i) have synthesized the crystals of (CoC10H10)0.25-TiSe2 by intercalation of CoC10H10 into TiS2 matrix as well as (ii) have investigated their properties at extreme conditions of ultrahigh pressure up to 20 GPa at room temperature conditions. We report the high-pressure behaviours of electrical resistance, thermoelectric power, compressibility, and thermal difference along a sample. By the changes of the above properties under pressure we have established the reversible insulator-semiconductor-metal transitions. Under pressure, the compound exhibited a change of its electrical resistance by about 8 orders and two inversions of thermopower sign. We performed six subsequent cycles of pressurisation-releasing and have established both reversibility of the changes and repeatability of the results. So, this layer crystal seemed to be a new functional material for wide applications. S.V.O. acknowledges the Japanese Society of the Promotion of Science (JSPS) for the financial support. The research was supported by the Russian Foundation for Basic Research (RFBR), Gr. No. 04-02-16178.