近日，美国加利福尼亚大学圣塔芭芭拉分校的Andrea F. Young及其研究团队取得一项新进展。经过不懈努力，他们揭示石墨烯分数量子霍尔点接触中的普适手性Luttinger液体行为。相关研究成果已于2023年11月3日在国际权威学术期刊《科学》上发表。

该研究团队报道了对连接整数与分数量子霍尔边缘态的点接触进行的电导测量，这些测量分别在填充因子为1和1/3的条件下进行。在弱耦合条件下，研究人员观察到了温度和电压的普遍二次标度。而在强耦合条件下，研究人员证明了分数化准粒子在点接触处发生了完美的Andreev反射。利用强耦合物理效应，他们成功实现了一种几乎无耗散的直流电压升压变压器。该变压器的增益直接来源于电荷的拓扑分数化特性。

据悉，一维导体通过Luttinger液体理论进行描述，该理论预测了在低电压状态下，单电子隧穿密度会呈现幂律抑制的现象。进一步地，当隧穿进入分数量子霍尔效应的单一孤立手性边缘态时，预测的标度指数将被量子化。

附：英文原文

Title: Universal chiral Luttinger liquid behavior in a graphene fractional quantum Hall point contact

Author: Liam A. Cohen, Noah L. Samuelson, Taige Wang, Takashi Taniguchi, Kenji Watanabe, Michael P. Zaletel, Andrea F. Young

Issue&Volume: 2023-11-03

Abstract: One-dimensional conductors are described by Luttinger liquid theory, which predicts a power-law suppression of the single-electron tunneling density of states at low voltages. The scaling exponent is predicted to be quantized when tunneling into a single isolated chiral edge state of the fractional quantum Hall effect. We report conductance measurements across a point contact linking integer and fractional quantum Hall edge states (at fillings 1 and 1/3, respectively). At weak coupling, we observe the predicted universal quadratic scaling with temperature and voltage. At strong coupling, we demonstrate perfect Andreev reflection of fractionalized quasiparticles at the point contact. We use the strong coupling physics to realize a nearly dissipationless direct current voltage step-up transformer, whose gain arises directly from topological fractionalization of electrical charge.

DOI: 10.1126/science.adf9728

Source: https://www.science.org/doi/10.1126/science.adf9728