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Heat Capacity of the 1D SDW system (TMTTF)2Br and 2D CDW system 1T-TaS2 in magnetic field

The equilibrium heat capacity of the 1D system (TMTTF)2Br with spin density wave and the 2D system 1T-TaS2 with charge density wave were investigated in the temperature range between 0.07K and 10K and in a magnetic field up to 10T. For both materials an additional contribution to the heat capacity was found below 1K, which is proportional to T^-2. This contribution is caused by low energy excitations with a broad spectrum of their relaxation time. The relaxation time is strongly temperature dependent and follows the Arrhenius law, i.e. the relaxation is a thermal activated process. For both materials the same absolute value of the T^-2 term and the same activation energy Ea/kB = 0.5K was found. In di® ; erence to (TMTTF)2Br, where the heat capacity is strongly field dependent, the heat capacity of 1T-TaS2 is constant up to 5T.

heat capacity; SDW; (TMTTF)2Br; CDW; 1T-TaS2; magnetic field

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