反铁磁链中Dzyaloshinskii-Moriya机制驱动矢量自旋手征束缚态的研究
Theoretical study of vector-spin-chirality bound state driven by the inverse Dzyaloshinskii-Moriya mechanism in the one-dimensional antiferromagnetic chain
郭幸 1李耀进 2姚梓萌1
作者信息
- 1. 西安文理学院 物理系,西安 710065
- 2. 西安交通大学 电信学部电子科学与工程学院,西安 710049
- 折叠
摘要
Dzyaloshinskii-Moriya(DM)相互作用驱动的矢量自旋手征态,能和声子发生耦合,具备非常丰富的物理现象.本论文以一维反铁磁链中自旋手征-声子耦合模型为基础,研究不同声子环境下,耦合强度对自旋手征动力学演化过程的影响规律.结果表明,对自旋S=1/2的系统,在不同的声子浴(sub-Ohm-ic(0＜s＜1),Ohmic(s=1),super-Ohmic(s＞1))中,均会在非相干到相干自旋涨落过程中产生无能隙一级相变,其来源是自旋手征束缚态的形成.相变发生的临界自旋-声子耦合强度正比于自旋涨落大小,反比于系统德拜频率.当自旋-声子耦合强度超过其临界值时,自旋手征束缚态的产生将极大地抑制非相干自旋涨落.
Abstract
There is a strong quantum fluctuation effect in the low-dimensional magnetic materials,and multiple interaction mechanisms can be induced by structural asymmetry or external field perturbation.Whereas the sys-tem possesses types of hidden multiple-spin ordering,such as spin-nematic state or spin-chirality state etc.Therefore,low-dimensional magnetic materials show a series of novel physical properties.The vector-spin-chirality bound state driven by the inverse Dzyaloshinskii-Moriya mechanism can be coupled with phonons and has richer physical phenomena.A one-dimensional antiferromagnetic chain with spin chirality-phonons cou-pling model is studied in the conditions of sub-Ohmic(0＜s＜1),Ohmic(s=1)and super-Ohmic(s＞1),respectively.We investigate in detail the time evolution of the spin chirality under different strengths of spin-phonon coupling but with same initial state.Our analytical study reveals that the system undergoes a gapless first-order phase transition by increasing the spin chirality-phonon interaction.The incoherent spin fluctuations can be strongly suppressed due to the formation of spin-chirality bound state driven by the spin-phonon cou-pling of Dzyaloshinskii-Moriya type.The ratio between the spin fluctuations and the Debye frequency of pho-nons determines the critical point of spin-phonon interaction in a fixed s,beyond which the gapped spin-chiral state is resulted in.Our research will provide theoretical guidance for obtaining long-term spin coherent systems in the applications of quantum transport and quantum storage.
关键词
自旋手征/反铁磁链/声子/DM相互作用/量子相变Key words
Spin chirality/Antiferromagnetic chain/Phonon/DM interaction/Quantum phase transition引用本文复制引用
基金项目
陕西省自然科学基础研究计划项目(2021JQ-790)
陕西省教育厅科研计划项目(20JK0868)
出版年
2024
国家科技期刊平台
NSTL
维普
万方数据