Low-Frequency Spin Dynamics in a Canted Antiferromagnet
Low-Frequency Spin Dynamics in a Canted Antiferromagnet
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DOI：
10.1126/science.1127094
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发表时间：
2006-07
期刊：
影响因子：
56.9
通讯作者：
N. Kumada;K. Muraki;Y. Hirayama
中科院分区：
文献类型：
--
作者：
N. Kumada;K. Muraki;Y. Hirayama
在紧密分离的二维电子系统中的电阻检测核自旋弛豫测量揭示了量子霍尔制度中的强低频电子自旋波动。随着温度的降低，自旋波动，表现为核自旋-晶格弛豫速率1/T1的急剧增强，继续增长到66毫开尔文的最低温度。观察到的1/T1发散行为信号的无隙自旋激发模式，是一个标志的倾斜反铁磁秩序。我们的数据表明，实现了一个二维系统的平面对称性破缺，其中波动不冻结时，接近零温度极限。
Resistively detected nuclear spin relaxation measurements in closely separated two-dimensional electron systems reveal strong low-frequency electron-spin fluctuations in the quantum Hall regime. As the temperature is decreased, the spin fluctuations, manifested by a sharp enhancement of the nuclear spin-lattice relaxation rate 1/T1, continue to grow down to the lowest temperature of 66 millikelvin. The observed divergent behavior of 1/T1 signals a gapless spin excitation mode and is a hallmark of canted antiferromagnetic order. Our data demonstrate the realization of a two-dimensional system with planar broken symmetry, in which fluctuations do not freeze out when approaching the zero temperature limit.