Current-driven quantum criticality in itinerant electron ferromagnets
Current-driven quantum criticality in itinerant electron ferromagnets
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DOI：
10.1103/physrevb.77.220404
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发表时间：
2008-04
影响因子：
3.7
通讯作者：
A. Mitra;A. Millis
中科院分区：
文献类型：
--
作者：
A. Mitra;A. Millis
我们确定了在铁磁-顺磁量子临界点附近，平面电流对二维巡回电子系统临界性质的影响。我们研究了一个模型，在该模型中，由于粒子和能量与底层衬底的交换，建立了一个非平衡的稳态。在有效作用中，电流不仅产生等于平均自由程数量级上的电压降的有效温度，而且还产生形式为$vec{j}\cdot\vec{nabla}$的对称性破缺项。发现对称性破缺对涨落和临界性质的影响很小，尽管(与以前的结果一致)如果转动自由度很重要，电流可以使经典有序态动态不稳定。
We determine the effect of an in-plane current flow on the critical properties of a 2d itinerant electron system near a ferromagnetic-paramagnetic quantum critical point. We study a model in which a nonequilibrium steady state is established as a result of exchange of particles and energy with an underlying substrate. the current $\vec{j}$ gives rise not only to an effective temperature equal to the voltage drop over a distance of order the mean free path, but also to symmetry breaking terms of the form $\vec{j}\cdot \vec{nabla}$ in the effective action. The effect of the symmetry breaking on the fluctuational and critical properties is found to be small although (in agreement with previous results) if rotational degrees of freedom are important, the current can make the classically ordered state dynamically unstable.