Nat Mater. 2014 Apr;13(4):356-9. doi: 10.1038/nmat3900.
When magnetic order is suppressed by frustrated interactions, spins form a highly correlated fluctuating 'spin liquid' state down to low temperatures. The magnetic order of local moments can also be suppressed when they are fully screened by conduction electrons through the Kondo effect. Thus, the combination of strong geometrical frustration and Kondo screening may lead to novel types of quantum phase transition. We report low-temperature thermodynamic measurements on the frustrated Kondo lattice Pr₂Ir₂O₇, which exhibits a chiral spin liquid state below 1.5 K as a result of the frustrated interaction between Ising 4f local moments and their interplay with Ir conduction electrons. Our results provide a first clear example of zero-field quantum critical scaling that emerges in a spin liquid state of a highly frustrated metal.
当磁有序被受挫相互作用抑制时,自旋会形成高度关联的波动“自旋液体”状态,直至低温。当局部磁矩完全被传导电子通过康登效应屏蔽时,其磁有序也会被抑制。因此,强几何受挫和康登屏蔽的组合可能会导致新型的量子相变。我们报告了在受挫的 Kondo 晶格 Pr₂Ir₂O₇上的低温热力学测量,其在 1.5 K 以下表现出手性自旋液体状态,这是由于 Ising 4f 局部磁矩之间的受挫相互作用及其与 Ir 传导电子的相互作用所致。我们的结果提供了在高度受挫金属的自旋液体状态中出现的零场量子临界标度的第一个明确实例。