Pressure-induced transition from a correlated insulator to a Fermi liquid observed in geometrically frustrated Hg2Ru2O7 pyrochlore
Pressure-induced transition from a correlated insulator to a Fermi liquid observed in geometrically frustrated Hg2Ru2O7 pyrochlore
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DOI：
10.1143/jpsj.76.063707
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发表时间：
2007-06-01
影响因子：
1.7
通讯作者：
Takagi, Hidenori
中科院分区：
文献类型：
--
作者：
Takeshita, Nao;Terakura, Chieko;Takagi, Hidenori
最近发现的氧化焦氯化物Hg2Ru2O7在温度接近107 K时表现出一阶金属绝缘体转变。通过测量高达12GPa的温度相关电阻率rho(T)，研究静水压力对M-I转变的影响。压力的施加抑制了低温绝缘状态，并最终导致在5gpa左右从相关绝缘体转变为金属。随着温度的降低，金属相中的rho(T)在T*附近迅速下降，类似于40 K，可能代表了相干-非相干交叉的开始，最终在低温下定义良好的T-2依赖性，表明相干准粒子的存在。所有这些结果都指出，在这个几何受挫系统的金属状态下，在相关驱动的金属-绝缘体转变附近，形成了质量增强的费米液体。
Recently discovered pyrochlore oxide, Hg2Ru2O7, shows a first order metal-insulator transition at T similar to 107 K. The effect of hydrostatic pressure on the M-I transition was studied by measuring the temperature dependent resistivity rho(T) up to 12GPa. The application of pressure suppressed the low temperature insulating state and eventually induced a transition from a correlated insulator to a metal at around 5 GPa. With decreasing temperature, rho(T) in the metallic phase showed a rapid decrease at around T* similar to 40 K, likely representing the onset of a coherent-incoherent crossover, and eventually a well defined T-2-dependence at low temperatures, indicative of the presence of coherent quasi-particles. All these results point the formation of a Fermi liquid with an enhanced mass in the metallic state of this geometrically frustrated system, located close proximity to the correlation driven metal-insulator transition.