论文标题
抗铁磁化合物EUCU2GE2的独特电子状态的价值转变的量子关键性
Quantum Criticality of Valence Transition for the Unique Electronic State of Antiferromagnetic Compound EuCu2Ge2
论文作者
论文摘要
通过最高10 GPA的电阻率测量值，压力对抗铁磁（AF）化合物EUCU2GE2的独特电子状态的影响已在10 mk至300 K的宽范围内测量。在环境压力下Tn = 15 K的neEL温度随着压力的增加而单调地增加，并在6.2 GPa时变为Tn = 27 K，但在PC = 6.5 GPA时突然下降至零，降至零，这表明欧盟的量子临界点（QCP）从几乎分裂的状态到具有数量的重量。基于rhomag的费米液体关系= rhomag0 + at^2的rhomag0和从低温电阻率获得的值和PC周围的尖锐峰值。从功率定律依赖性rhomag = rhomag0 + bt^n获得的指数n显然小于p = pc =6。5gpa的1.5，这是在AF-QCP上预期的。这些结果表明，PC与PV一致，对应于价转换压力PV的量子临界。根据广义的Kadowaki-Woods关系估算的电子特异性热系数在PC周围约为510 MJ/mol K^2，这表明形成了一个重毛状状态。
The effect of pressure on the unique electronic state of the antiferromagnetic (AF) compound EuCu2Ge2 has been measured in a wide temperature range from 10 mK to 300 K by electrical resistivity measurements up to 10 GPa. The Neel temperature of TN = 15 K at ambient pressure increases monotonically with increasing pressure and becomes a maximum of TN = 27 K at 6.2 GPa but suddenly drops to zero at Pc = 6.5 GPa, suggesting the quantum critical point (QCP) of the valence transition of Eu from a nearly divalent state to that with trivalent weight. The rhomag0 and A values obtained from the low-temperature electrical resistivity based on the Fermi liquid relation of rhomag = rhomag0 + AT^2 exhibit huge and sharp peaks around Pc. The exponent n obtained from the power law dependence rhomag = rhomag0 + BT^n is clearly less than 1.5 at P = Pc = 6. 5 GPa, which is expected at the AF-QCP. These results indicate that Pc coincides with Pv, corresponding to the quantum criticality of the valence transition pressure Pv. The electronic specific heat coefficient, estimated from the generalized Kadowaki-Woods relation, is about 510 mJ/mol K^2 around Pc, suggesting the formation of a heavy-fermion state.
