We examine the stability of the valence bond solid (VBS) phase against the Dzyaloshinskii-Moriya (DM) interaction in the bipartite lattice. Despite the VBS is vulnerable against the antiferromagnetic interaction, for example in the Q-J model proposed by Sandvik, where the quantum phase transition occurs at $J^*/Q = 0.04$, we found that on the contrary the VBS is very stable against the DM interaction. The quantum phase transition does not occur until D/Q goes to infinity, where D is the strength of the DM interaction. The VBS in the ALKT model and the Haldane gap system also exhibit the same property.
Using relativistic first-principles calculations, we show that the chemical trend of Dzyaloshinskii-Moriya interaction (DMI) in 3d-5d ultrathin films follows Hund's first rule with a tendency similar to their magnetic moments in either the unsupported 3d monolayers or 3d-5d interfaces. We demonstrate that, besides the spin-orbit coupling (SOC) effect in inversion asymmetric noncollinear magnetic systems, the driving force is the 3d orbital occupation and their spin flip/mixing processes with the spin-orbit active 5d states control directly the sign and magnitude of the DMI. The magnetic chiral…
We present a comprehensive theory of the magnetic phases in monolayer nickel-based Janus dihalides (NiIBr, NiICl, NiBrCl) through a combination of first-principles calculations and atomistic simulations. Phonon band structure calculations and finite temperature molecular dynamics simulations show that Ni-dihalide Janus monolayers are stable. The parameters of the interacting spin Hamiltonian extracted from ab initio calculations show that nickel-dihalide Janus monolayers exhibit varying degrees of magnetic frustration together with a large Dzyaloshinskii-Moriya interaction due to their inheren…
Weak antiferromagnetism due to Dzyaloshinskii-Moriya interaction in Ba$_3$Cu$_2$O$_4$Cl$_2$
反铁磁绝缘铜氧化物Ba $_3$ Cu $_2$ O $_4$ Cl $_2$含有折叠的CuO $_2$链，每个晶胞具有四个磁性铜离子（$S=1/2$）。一个潜在的多轨道哈伯德模型制定和超交换理论的发展，以获得一个有效的自旋哈密顿量的铜酸盐。得到的自旋哈密顿量除了包含各向同性交换作用外，还包含一个Dzyaloshinskiii-Moriya项和一个更弱的对称各向异性交换项.相应的Dzyaloshinskiii-Moriya矢量的每个磁性Cu-Cu键链中揭示了一个定义良好的空间秩序。超交换理论和互补群理论的考虑，都导致了关于这种秩序的性质的相同结论。的基态磁特性的推导模型的分析导致预测的反铁磁结构的一个额外的非共线调制。这种弱反铁磁性仅限于其中一个铜亚晶格。
Comment on "Theory of helimagnons in itinerant quantum systems" by D.Belitz, T.K.Kirpatrick and A.Rosch and "Cubic magnets with Dzyaloshinskii-Moriya interaction at low temperatures" by S.V.Maleyev
对D.Belitz、T.K.Kirpatrick和A.Rosch的“巡回量子系统中的helimagnons理论”和S. V. Maleyev的“低温下具有Dzyaloshinskiii-Moriya相互作用的立方磁体”的评论
This Topical Review presents an overview of the recent experimental results on the quantitative determination of the magnetic exchange parameters in ultrathin magnetic films and multilayers, grown on different substrates. The experimental approaches to probe both the symmetric Heisenberg as well as the antisymmetric Dzyaloshinskii--Moriya exchange interaction in ultrathin magnetic films and at interfaces are discussed in detail. It is explained how the experimental spectrum of magnetic excitations can be used to quantify the strength of these interactions.
We consider a class of one-dimensional compass models with staggered Dzyaloshinskii-Moriya exchange interactions in an external transverse magnetic field. Based on the exact solution derived from Jordan-Wigner approach, we study the excitation gap, energy spectra, spin correlations and critical properties at phase transitions. We explore mutual effects of the staggered Dzyaloshinskii-Moriya interaction and the magnetic field on the energy spectra and the ground-state phase diagram. Thermodynamic quantities including the entropy and the specific heat are discussed, and their universal scalings …
Relationship between ferroelectricity and Dzyaloshinskii-Moriya interaction in multiferroics and the effect of bond-bending
我们研究了多铁性的微观机制，特别是使用“自旋电流”模型（Hosho Katamoto，Naoto Nagaosa和Aleander V. Balatsky，Phys. Rev. Lett. 95，057205（2005））。从一个具有螺旋自旋的系统出发，求解了电子波函数的形式，并分析了它们的特性。铁电性与Dzyaloshinskiii-Moriya相互作用的关系（I. Dzyaloshinskii，J.Phys.Chem.Solids4，241（1958）和T. Moriya，Phys.Rev.120，91（1960））是明确建立的。电极化的强度与磁序波矢之间也有简单的关系。最后，我们证明了过渡金属氧化物中存在的键弯曲可以增强铁电性。
Monoaxial chiral magnets can form a noncollinear twisted spin structure called the chiral helimagnetic state. We study magnetic properties of such a chiral helimagnetic state, with emphasis on the effect of itinerant electrons. Modeling a monoaxial chiral helimagnet by a one-dimensional Kondo lattice model with the Dzyaloshinskii--Moriya interaction, we perform a variational calculation to elucidate the stable spin configuration in the ground state. We obtain a chiral helimagnetic state as a candidate for the ground state, whose helical pitch is modulated by the model parameters: the Kondo cou…
Dzyaloshinskii-Moriya interaction in NaV$_2$O$_5$: a microscopic study
本文提出了准一维过渡金属氧化物NaV $_2$ O $_5$的磁交换和喇曼散射的统一解释。基于团簇模型方法，给出了交换积分和拉曼算符的显式表达式。它表明，电子结构和Dzyaloshinskiii-Moriya相互作用的组合，允许在这种材料中的对称性，是负责有限的拉曼截面产生两个，一个和两个磁振子散射振幅。
We have studied the effect of the Dzyaloshinskii-Moriya interaction on kagome Heisenberg anti-ferromagnet using Schwinger boson mean field theory (SBMFT). Within SBMFT framework, Messio et al had argued that the ground state of kagome antiferromagnet is possibly a chiral topological spin liquid (Phys. Rev. Lett. 108, 207204 (2012)). Thus, we have computed zero-temperature ground state phase diagram considering the time-reversal breaking states as well as fully symmetric Ansätze. We discuss the relevance of these results in experiments and other studies. Finally, we have computed the static and…
The properties of two quantum spin chain materials, K$_2$CuSO$_4$Cl$_2$ and K$_2$CuSO$_4$Br$_2$, are studied by a variety of experimental techniques, including bulk measurements, neutron spectroscopy and ESR. The hierarchy of relevant terms in the magnetic Hamiltonian is established. It is shown that these two compounds feature substantial Dzyaloshinskii-Moriya (DM) interactions that are uniform within each chain, but antiparallel in adjacent chains. The result is a peculiar type of frustration of inter-chain interactions, which leads to an unusual field-temperature phase diagram.
Motivated by recent synthetic and theoretical progress we consider magnetism in crystals of multi-nuclear organometallic complexes. We calculate the Heisenberg symmetric exchange and the Dzyaloshinskii-Moriya antisymmetric exchange. We show how, in the absence of spin-orbit coupling, the interplay of electronic correlations and quantum interference leads to a quasi-one dimensional effective spin model in a typical tri-nuclear complex, Mo$_3$S$_7$(dmit)$_3$, despite its underlying three dimensional band structure. We show that both intra- and inter-molecular spin-orbit coupling can cause an eff…
On the two-dimensional non-linear $Σ$-model describing a ferromagnet with Dzyaloshinskii-Moriya interaction, we build three families of exact static solutions depending on a single Cartesian variable. One of them describes a clockwise helix configuration, that characterizes the ground state of the system. A second one corresponds to a counterclockwise helix, representing an excited state. These two families of solutions are parameterized by a continuous parameter that depends on the magnetic field and the Dzyaloshinskii-Moriya coupling. Finally, the third family exists only for isolated values…
We report a combined analytical and density matrix renormalized group study of the antiferromagnetic XXZ spin-1/2 Heisenberg chain subject to a uniform Dzyaloshinskii-Moriya (DM) interaction and a transverse magnetic field. The numerically determined phase diagram of this model, which features two ordered Ising phases and a critical Luttinger liquid one with fully broken spin-rotational symmetry, agrees well with the predictions of Garate and Affleck [Phys. Rev. B 81, 144419 (2010)]. We also confirm the prevalence of the N z Néel Ising order in the regime of comparable DM and magnetic field ma…
We study the magnetic properties of the two-dimensional anisotropic antiferromagnetic spin-1/2 Heisenberg model with Dzyaloshinskii-Moriya interaction and in-plane frustration included. The method of spin Green functions within the framework of Tyablikov's random-phase-approximation decoupling scheme is used in order to derive expressions for the spin-wave spectrum, sublattice magnetization and transition temperature. Based on these expressions we perform a detailed analysis of the influence of varying values of model parameters on its magnetic properties. The model is also applied to the high…
The electron spin resonance spectrum of a quasi 1D S=1/2 antiferromagnet K2CuSO4Br2 was found to demonstrate an energy gap and a doublet of resonance lines in a wide temperature range between the Curie--Weiss and Neèl temperatures. This type of magnetic resonance absorption corresponds well to the two-spinon continuum of excitations in S=1/2 antiferromagnetic spin chain with a uniform Dzyaloshinskii--Moriya interaction between the magnetic ions. A resonance mode of paramagnetic defects demonstrating strongly anisotropic behavior due to interaction with spinon excitations in the main matrix is …
We theoretically study magnetic and topological properties of antiferromagnetic kagome spin systems in the presence of both in- and out-of-plane Dzyaloshinskii-Moriya interactions. In materials such as the iron jarosites, the in-plane interactions stabilize a canted noncollinear "umbrella" magnetic configuration with finite scalar spin chirality. We derive expressions for the canting angle, and use the resulting order as a starting point for a spin-wave analysis. We find topological magnon bands, characterized by non-zero Chern numbers. We calculate the magnon thermal Hall conductivity, and pr…
A preponderance of evidence suggests that the ground state of the nearest-neighbor $S = 1/2$ antiferromagnetic Heisenberg model on the kagome lattice is a gapless spin liquid. Many candidate materials for the realization of this model possess in addition a Dzyaloshinskii-Moriya (DM) interaction. We study this system by tensor-network methods and deduce that a weak but finite DM interaction is required to destabilize the gapless spin-liquid state. The critical magnitude, $D_c/J \simeq 0.012(2)$, lies well below the DM strength proposed in the kagome material herbertsmithite, indicating a need t…
We investigate an antiferromagnetic spin-$1$ Heisenberg chain in the presence of Dyzaloshinskii-Moriya interactions (DMI) and an external magnetic field. We study the resulting spin chain using a combination of numerical and analytical techniques. Using DMRG simulations to determine the spectral gap and the entanglement spectrum, we map out the phase diagram as a function of magnetic field strength and DMI strength. We provide a qualitative interpretation for these numerical findings by mapping the spin-$1$ chain on a spin-$1/2$ ladder and using a bosonization approach.
We study in this paper magnetic properties of a system of quantum Heisenberg spins interacting with each other via a ferromagnetic exchange interaction J and an in-plane Dzyaloshinskii-Moriya interaction D. The non-collinear ground state due to the competition between J and D is determined. We employ a self-consistent Green'function theory to calculate the spin-wave spectrum and the layer magnetizations at finite T in two and three dimensions as well as in a thin film with surface effects. Analytical details and the validity of the method are shown and discussed.
The longitudinal spin-Seebeck effect (SSE) in magnetic insulator$|$non-magnetic metal heterostructures has been theoretically studied primarily with the assumption of an isotropic interfacial exchange coupling. Here, we present a general theory of the SSE in the case of an antisymmetric Dzyaloshinskii-Moriya interaction (DMI) at the interface, in addition to the usual Heisenberg form. We numerically evaluate the dependence of the spin current on the temperature and bulk DMI using a pyrochlore iridate as a model insulator with all-in all-out (AIAO) ground state configuration. We also compare th…
We propose a new type of Dzyaloshinskii-Moriya (DM) interactions which act on high-rank multipolar moments such as quadrupolar and octupolar moments. Here we consider 5d1 systems with broken spatial inversion symmetry, where the interplay of electron correlation, the spin-orbit coupling, and inversion symmetry breaking plays a crucial role. Using a numerical diagonalization on a two-site multiorbital Hubbard model, we reveal that anti-symmetric products of multipole operators have finite expectation values, indicating the existence of DM interactions for multipoles. We also find that the spin-…
We observe and explain theoretically a dramatic evolution of the Dzyaloshinskii-Moriya interaction in the series of isostructural weak ferromagnets, MnCO$_3$, FeBO$_3$, CoCO$_3$ and NiCO$_3$. The sign of the interaction is encoded in the phase of x-ray magnetic diffraction amplitude, observed through interference with resonant quadrupole scattering. We find very good quantitative agreement with first-principles electronic structure calculations, reproducing both sign and magnitude through the series, and propose a simplified `toy model' to explain the change in sign with 3 d shell filling. The…
Single-ion anisotropy, Dzyaloshinskii-Moriya interaction and negative magnetoresistance of the spin-1/2 pyrochlores R2V2O7
采用密度泛函方法研究了自旋为1/2的高温超导体R2 V2 O 7的电子和磁性.与通常的看法相反，自旋为1/2的V4+离子被发现具有显著的易轴单离子各向异性。的|D/J|从Lu 2 V2 O 7的磁振子量子霍尔效应推导出的比率，其中J是最近邻自旋交换，D是Dzyaloshinskiii-Moriya参数，远大于从我们的计算估计的值（即，0.32与0.05）。我们发现，这种差异是由于忽略的V4+离子的单离子各向异性，和观察到的负磁阻R2 V2 O 7产生一个新的机制。
