Search for a quantum spin liquid in the Kitaev honeycomb lattice, alpha-RuCl3

在 Kitaev 蜂窝晶格中寻找量子自旋液体 α-RuCl3

• 批准号: 391462523
• 负责人: Dr. Seung-Ho Baek, Ph.D.
• 金额: --
• 依托单位: Institut für Festkörperforschung
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/391462523?language=en
• 关键词: Search; quantum; spin; liquid; Kitaev

The key objective of this proposal is to search for a Kitaev quantum spin liquid (QSL) and relevant novel quasiparticle excitations emerging from spin fractionalization by means of nuclear magnetic resonance (NMR). For this purpose, we take alpha-RuCl3 as a model system for the realization of a Kitaev QSL. Since the ground state of alpha-RuCl3 is in the proximity of a QSL, it should be highly sensitive to the strengths and the signs of the couplings in the Kitaev Hamiltonian. Thus one can fine-tune the ground state of alpha-RuCl3 by manipulating the coupling parameters in the Hamiltonian in a variety of avenues:(1) Application of very high magnetic fields(2) Magnetic site dilution with nonmagnetic ions, e.g. Ir3+ (S=0)(3) Substituting Ru with paramagnetic impurities, e.g. Cr3+ (S=3/2)(4) Application of chemical pressure by substituting Cl with other halide elements with larger radius (Br and I) (5) Intercalating alkali elements (Na or K) between the layers to incorporate charge carriers to induce novel metallic phases.Each of these avenues has its own merit and potential, and thus will provide a different piece of information that are useful for the ultimate understanding of Kitaev physics.

该方案的主要目的是利用核磁共振技术寻找Kitaev量子自旋液体(QSL)及其自旋分馏产生的新的准粒子激发。为此，我们以α-RuCl3作为实现Kitaev QSL的模型系统。由于α-RuCl3的基态在QSL附近，它对Kitaev哈密顿量中耦合的强度和符号应该是高度敏感的。因此，人们可以通过在各种途径中操纵哈密顿量中的耦合参数来微调α-RuCl3的基态：(1)施加非常高的磁场(2)用非磁性离子稀释磁位，例如IR3+(S=0)(3)用顺磁杂质替代Ru，例如Cr3+(S=3/2)(4)通过用其他具有更大半径的卤化物元素(Br和I)替代Cl来施加化学压力(5)在层之间插入碱性元素(Na或K)以结合电荷载流子以诱导新的金属相。这些途径中的每一种都有其各自的优点和潜力，因此将提供一条不同的信息，对最终理解基塔耶夫物理学是有用的。

项目成果

Separate tuning of nematicity and spin fluctuations to unravel the origin of superconductivity in FeSe

• DOI: 10.1038/s41535-020-0211-y
• 发表时间: 2020-01
• 期刊: npj Quantum Materials
• 影响因子: 5.7
• 作者: S. Baek;J. Ok;J. S. Kim;S. Aswartham;I. Morozov;D. Chareev;T. Urata;K. Tanigaki;Y. Tanabe

Nematicity and magnetism in LaFeAsO single crystals probed by As 75 nuclear magnetic resonance

• DOI: 10.1103/physrevb.97.180405
• 发表时间: 2018-02
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: J. Ok;S. H. Baek;D. Efremov;R. Kappenberger;S. Aswartham;Jun Sung Kim;J. V. D. Brink;B. Büchner