engleski

Long-time heat release in the quasi-1D conductor (TMTSF)(2)PF6 at low temperatures

We have measured the heat capacity and the heat release of the quasi-1D conductor (TMTSF)(2)PF6 in its spin-density wave ground state. Below 1 K the presence of low-energy excitations is at the origin of slow heat release over time scales from about 1 s up to 10(5) s. In a first attempt, we analyzed this behaviour with a modified version of the standard tunneling model used in the case of amorphous solids, introducing a short-time cut-off in the distribution of the relaxation times of tunneling states. A remarkable feature of the heat release in (TMTSF)(2)PF6 is its high absolute value, which is 3-4 orders of magnitude larger than in structural glasses. The heat capacity contains a Schottky and a quasi-linear term.

spin-density wave; low-energy excitations; amorphous solids; complex relaxation

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