近日，美国加州大学伯克利分校的Hongyuan Li&Feng Wang及其研究团队取得一项新进展。经过不懈努力，他们成功在范德华异质结构中成像可调谐卢廷格液体系统。相关研究成果已于2024年7月3日在国际权威学术期刊《自然》上发表。

该研究团队证明了范德华异质结构中的层堆叠畴壁(DWs)形成了一个广泛可调谐的卢廷格液体系统，包括隔离阵列和耦合阵列。研究人员利用扫描隧道显微镜成像了DWs卢廷格液体在不同相互作用机制下由电子密度调节的演化过程。在低载流子密度下，单DWs高度容易受到与自旋非相干卢廷格液体一致的魏格纳结晶的影响，而在中等密度下，由于增强的磁弹性耦合，形成了二聚化的魏格纳晶体。DWs的周期阵列表现出链内和链间相互作用之间的交互，从而产生新的量子相。

在低电子密度下，链间相互作用占主导地位，诱导出由交错构型锁相一维维格纳晶体组成的二维电子晶体。增加的电子密度导致链内波动势占主导地位，导致电子在链内呈现代数相关衰减的有序排列，而在链间则呈现出无序状态，形成了电子近晶液晶相。这项研究工作表明，二维异质结构中的层堆叠DWs为探索卢廷格液体物理提供了机会。

据悉，一维(1D)相互作用的电子通常被描述为具有本质上不同于高维费米液体性质的卢廷格液体。在材料系统中，一维电子表现出奇异的量子现象，可以通过一维链内和一维链间的电子相互作用来调节，但它们的实验表征可能具有挑战性。

附：英文原文

Title: Imaging tunable Luttinger liquid systems in van der Waals heterostructures

Author: Li, Hongyuan, Xiang, Ziyu, Wang, Tianle, Naik, Mit H., Kim, Woochang, Nie, Jiahui, Li, Shiyu, Ge, Zhehao, He, Zehao, Ou, Yunbo, Banerjee, Rounak, Taniguchi, Takashi, Watanabe, Kenji, Tongay, Sefaattin, Zettl, Alex, Louie, Steven G., Zaletel, Michael P., Crommie, Michael F., Wang, Feng

Issue&Volume: 2024-07-03

Abstract: One-dimensional (1D) interacting electrons are often described as a Luttinger liquid having properties that are intrinsically different from those of Fermi liquids in higher dimensions. In materials systems, 1D electrons exhibit exotic quantum phenomena that can be tuned by both intra- and inter-1D-chain electronic interactions, but their experimental characterization can be challenging. Here we demonstrate that layer-stacking domain walls (DWs) in van der Waals heterostructures form a broadly tunable Luttinger liquid system, including both isolated and coupled arrays. We have imaged the evolution of DW Luttinger liquids under different interaction regimes tuned by electron density using scanning tunnelling microscopy. Single DWs at low carrier density are highly susceptible to Wigner crystallization consistent with a spin-incoherent Luttinger liquid, whereas at intermediate densities dimerized Wigner crystals form because of an enhanced magneto-elastic coupling. Periodic arrays of DWs exhibit an interplay between intra- and inter-chain interactions that gives rise to new quantum phases. At low electron densities, inter-chain interactions are dominant and induce a 2D electron crystal composed of phased-locked 1D Wigner crystal in a staggered configuration. Increased electron density causes intra-chain fluctuation potentials to dominate, leading to an electronic smectic liquid crystal phase in which electrons are ordered with algebraical correlation decay along the chain direction but disordered between chains. Our work shows that layer-stacking DWs in 2D heterostructures provides opportunities to explore Luttinger liquid physics.

DOI: 10.1038/s41586-024-07596-6

Source: https://www.nature.com/articles/s41586-024-07596-6