可能存在 GaAs 量子线中螺旋核自旋有序的证据。

Possible evidence for helical nuclear spin order in GaAs quantum wires.

机构信息

Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland.

Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.

出版信息

Phys Rev Lett. 2014 Feb 14;112(6):066801. doi: 10.1103/PhysRevLett.112.066801. Epub 2014 Feb 10.

DOI:10.1103/PhysRevLett.112.066801

PMID:24580700

Abstract

We present transport measurements of cleaved edge overgrowth GaAs quantum wires. The conductance of the first mode reaches 2e(2)/h at high temperatures T≳10 K, as expected. As T is lowered, the conductance is gradually reduced to 1e(2)/h, becoming T independent at T≲0.1 K, while the device cools far below 0.1 K. This behavior is seen in several wires, is independent of density, and not altered by moderate magnetic fields B. The conductance reduction by a factor of 2 suggests lifting of the electron spin degeneracy in the absence of B. Our results are consistent with theoretical predictions for helical nuclear magnetism in the Luttinger liquid regime.

摘要

我们呈现了对劈开边缘过生长 GaAs 量子线的输运测量结果。在高温 T≳10 K 下，正如预期的那样，第一模式的电导达到了 2e(2)/h。随着 T 的降低，电导逐渐降低到 1e(2)/h，在 T≲0.1 K 时变得与 T 无关，而器件在远低于 0.1 K 的温度下冷却。这种行为在几条线中都可以看到，与密度无关，并且不受中等磁场 B 的影响。电导降低了 2 倍，这表明在没有 B 的情况下电子自旋简并度被解除。我们的结果与在 Luttinger 液体区的螺旋核磁性的理论预测一致。