Crossover from thermal hopping to quantum tunneling in Mn12Ac

Article

关键词: JOSEPHSON-JUNCTIONS;    DECAY;    MAGNETIZATION;    TRANSITIONS;    TEMPERATURES;    MOLECULES;    VACUUM;    STATE;    LIMIT;   

DOI  :  10.1103/PhysRevB.59.6309

来源: SCIE

【 摘 要 】

The crossover from thermal hopping to quantum tunneling is studied. We show that the decay rate Gamma with dissipation can accurately be determined near the crossover temperature. Besides considering the Wentzel-Kramers-Brillouin (WKB) exponent, we also calculate contribution of the fluctuation modes around the saddle point and give an extended account of a previous study of crossover region. We deal with two dangerous fluctuation modes whose contribution cannot be calculated by the steepest descent method and show that higher-order couplings between the two dangerous modes need to he taken into consideration. At last the crossover from thermal hopping to quantum tunneling in the molecular magnet Mn12Ac is studied. [S0163-1829(99)03409-8].

【 授权许可】

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