Condensed Molecular Materials Laboratory, RIKEN, The Institute of Physical and Chemical Research, 2-1, Hirosawa, Wako, Saitama 351-0198, Japan.
Advanced Meson Science Laboratory, RIKEN Nishina Center, 2-1, Hirosawa, Wako, Saitama 351-0198, Japan.
Phys Rev Lett. 2015 Mar 13;114(10):106401. doi: 10.1103/PhysRevLett.114.106401. Epub 2015 Mar 11.
Pressure dependence of the conductivity and thermoelectric power is measured through the Mott transition in the layer organic conductor EtMe_{3}P[Pd(dmit){2}]{2}. The critical behavior of the thermoelectric effect provides a clear and objective determination of the Mott-Hubbard transition during the isothermal pressure sweep. Above the critical end point, the metal-insulator crossing, determined by the thermoelectric effect minimum value, is not found to coincide with the maximum of the derivative of the conductivity as a function of pressure. We show that the critical exponents of the Mott-Hubbard transition fall within the Ising universality class regardless of the dimensionality of the system.
通过在层状有机导体 EtMe_3P[Pd(dmit)_2]_2 中的 Mott 转变测量了电导率和热电势的压力依赖性。热电效应的临界行为为等温压力扫描过程中的 Mott-Hubbard 转变提供了一个清晰而客观的确定。在临界点以上，由热电效应最小值确定的金属-绝缘体转变，与电导率作为压力的函数的导数最大值不重合。我们表明，Mott-Hubbard 转变的临界指数属于伊辛普遍类，与系统的维度无关。
