近日，美国康奈尔大学的Kin Fai Mak&Jie Shan及其研究团队取得一项新进展。经过不懈努力，他们成功观察到阻挫莫尔哈伯德
本文报道了在三角形晶格MoTe2/WSe2摩尔双层中直接观测到自旋极化子。在晶格填充因子低于1的条件下，自旋极化子相出现，并通过超磁跃迁与完全自旋极化相分离。研究人员发现，自旋极化子是一种自旋为-3/2的粒子，其结合能与动能跳跃能相称。这项研究结果将有助于探索自旋极化子赝隙金属、自旋极化子配对和其他三角晶格莫尔材料中的新现象。
据悉，电子的动能在磁性中起着关键的作用。虚电子跳跃促进绝缘体中的反铁磁性，而实电子跳跃过程通常有利于铁磁性。然而，在动力学阻挫系统中，如空穴掺杂的三角形晶格莫特绝缘体，实跳跃已被证明有利于反铁磁性。动力学阻挫也被预测会在中间磁场中诱导出一种新的准粒子，一种掺杂空穴的束缚态和一种被称为自旋极化子的自旋翻转，这可能会形成一种不寻常的金属态。
附：英文原文
Title: Observation of spin polarons in a frustrated moiré Hubbard system
Author: Tao, Zui, Zhao, Wenjin, Shen, Bowen, Li, Tingxin, Knppel, Patrick, Watanabe, Kenji, Taniguchi, Takashi, Shan, Jie, Mak, Kin Fai
Issue&Volume: 2024-03-01
Abstract: The electron’s kinetic energy plays a pivotal role in magnetism. While virtual electron hopping promotes antiferromagnetism in an insulator, real hopping processes usually favour ferromagnetism. However, in kinetically frustrated systems such as hole-doped triangular lattice Mott insulators, real hopping has instead been shown to favour antiferromagnetism. Kinetic frustration has also been predicted to induce a new quasiparticle, a bound state of the doped hole and a spin flip called a spin polaron, at intermediate magnetic fields, which could form an unusual metallic state. Here we report the direct observation of spin polarons in triangular lattice MoTe2/WSe2 moiré bilayers. A spin polaron phase emerges at a lattice filling factor just below 1 and is separated from the fully spin-polarized phase by a metamagnetic transition. We determine that the spin polaron is a spin-3/2 particle and that its binding energy is commensurate with the kinetic hopping energy. Our results will enable the exploration of spin polaron pseudogap metals, spin polaron pairing and other new phenomena in triangular lattice moiré materials.
DOI: 10.1038/s41567-024-02434-y
Source: https://www.nature.com/articles/s41567-024-02434-y