Uniform Dzyaloshinskii-Moriya Interaction Research Articles

Anomalous behavior in entanglement speed profile through spin chains.

The origin of the uniform Dzyaloshinskii-Moriya interaction (DMI), which is responsible for the creation of chiral magnetism, has been the subject of extensive research. Recently, modern technology has allowed for its production and utilization in a modulated form. Not only can magnetic phases of spin chains be enriched by the presence of such a potential as detailed in Japaridze etal. [Phys. Rev. E 104, 014134 (2021)10.1103/PhysRevE.104.014134], but the capacity of such systems for information transmission is also greatly enhanced. The current paper examines the impact of a staggered pattern of DMI (STDMI) on a chain with a substrate XX Heisenberg interaction. It is demonstrated how enhancing the intensity of this coupling improves the propagation of an entangled quantum state. Additionally, as our analysis has shown, the initial condition over the system's state has a profound effect on the speed at which entanglement spreads. The aberrant behavior of the entanglement's speed profile in response to fine-tuning of the phase factor which adjusts the initial state is the focus of this paper. This anomalous behavior is characterized by dramatic drops in speed for certain phase factor values. We have also shown that, using wave interference principles, we can predict exactly why these phenomena occur. This research will pave the way for additional studies on STDMI and its potential applications in the field of quantum information.

Skyrmion based universal logic gates and computation operation

Swirling spin configurations with a non-trivial topological state are popularly known as magnetic skyrmions. They are often observed in magnetic thin films with perpendicular magnetic anisotropy and Dzyaloshinskii–Moriya interaction (DMI). Due to their small size and non-collinear spin texture, they are being considered as a potential candidate for spintronic devices such as data storage devices, and logic-based devices. These skyrmions have distinct properties and interactions, that can be utilized to control their movement by applying an external electric current. In this work, we have successfully demonstrated the operation of skyrmion-based universal NAND and NOR logic gates. We have further performed arithmetic addition of two and three single-bit by using a half and full adder, fabricated based on the XOR and AND gates. We have observed that the presence of only uniform DMI is not enough to achieve all logic operations. The presence of a negative DMI at the edges is crucial in achieving proper logic operations. The findings are very important for the realization of skyrmion-based logic and computational operations.

Experimental Studies of Dzyaloshinskii–Moriya Interaction in Quantum Spin Systems: High-frequency High-field Electron Spin Resonance (ESR) Measurements

In this review, the importance of the Dzyaloshinskii–Moriya Interaction (DMI) to the magnetic properties of quantum spin systems is discussed mainly focusing on the determination of or understanding the role of DMI extracted from high-frequency high-field electron spin resonance (ESR) measurements. This review includes the ESR theories of the S = 1/2 one-dimensional (1D) antiferromagnet with the staggered field (Oshikawa–Affleck theory) and with the uniform DMI, and several related experimental results are shown. Then, the proposed mechanisms of the singlet–triplet transition in quantum spin systems together with the ESR selection rules are introduced in connection with various experimental results. Finally, the role of DMI in the ground state of kagome lattice antiferromagnets and the honeycomb lattice antiferromagnet is discussed with some experimental results.

Dimensional reduction and incommensurate dynamic correlations in the S=frac{1}{2} triangular-lattice antiferromagnet Ca3ReO5Cl2

The observation of spinon excitations in the S=frac{1}{2} triangular antiferromagnet Ca3ReO5Cl2 reveals a quasi-one-dimensional (1D) nature of magnetic correlations, in spite of the nominally 2D magnetic structure. This phenomenon is known as frustration-induced dimensional reduction. Here, we present high-field electron spin resonance spectroscopy and magnetization studies of Ca3ReO5Cl2, allowing us not only to refine spin-Hamiltonian parameters, but also to investigate peculiarities of its low-energy spin dynamics. We argue that the presence of the uniform Dzyaloshinskii-Moriya interaction (DMI) shifts the spinon continuum in momentum space and, as a result, opens a zero-field gap at the Γ point. We observed this gap directly. The shift is found to be consistent with the structural modulation in the ordered state, suggesting this material as a perfect model triangular-lattice system, where a pure DMI-spiral ground state can be realized.

Spin relaxation in Cs2CuCl4−xBrx

The quantum-spin $S=1/2$ chain system ${\mathrm{Cs}}_{2}\mathrm{Cu}{\mathrm{Cl}}_{4}$ is of high interest due to competing antiferromagnetic intrachain $J$ and interchain exchange ${J}^{\ensuremath{'}}$ interactions and represents a paramount example for Bose-Einstein condensation of magnons [R. Coldea et al., Phys. Rev. Lett. 88, 137203 (2002)]. Substitution of chlorine by bromine allows tuning the competing exchange interactions and corresponding magnetic frustration. Thereby, anisotropic exchange contributions may be decisive for the resulting ground state. Here we report on electron spin resonance (ESR) in single crystals of ${\mathrm{Cs}}_{2}\mathrm{Cu}{\mathrm{Cl}}_{4\ensuremath{-}x}{\mathrm{Br}}_{x}$ with the aim to analyze the evolution of these anisotropic exchange contributions. The main source of the ESR linewidth is attributed to the uniform Dzyaloshinskii-Moriya interaction. The vector components of the Dzyaloshinskii-Moriya interaction are determined from the angular dependence of the ESR spectra using a high-temperature approximation. The obtained results support the site selectivity of the Br substitution suggested from the evolution of lattice parameters and magnetic susceptibility dependent on the Br concentration.

Influence of Dzyaloshinskii-Moriya interaction and external fields on quantum entanglement in half-integer spin one-dimensional antiferromagnets

The effect of uniform Dzyaloshinskii-Moriya interaction (antisymmetric spin coupling) and arbitrary oriented external magnetic fields in the x and z directions hx, hy, on quantum entanglement is investigated in the quantum spin-1/2 one-dimensional Heisenberg antiferromagnetic model. The Von Neumann entropy of quantum entanglement is calculated employing Abelian bosonization and density matrix renormalization group. We investigate the influence of quantum phase transition of three competing phases (Neel phase, dimerized phase and gapless Luttinger liquid phase) on quantum entanglement at zero-temperature.

Spin gap in the quasi-one-dimensional S=12 antiferromagnet K2CuSO4Cl2

Electron spin resonance experiments in the quasi-1D S=1/2 antiferromagnet K$_2$CuSO$_4$Cl$_2$ reveal opening of a gap in absence of magnetic ordering, as well as an anisotropic shift of the resonance magnetic field. These features of magnetic excitation spectrum are explained by a crossover between a gapped spinon-type doublet ESR formed in a 1D antiferromagnet with uniform Dzyaloshinskii-Moriya interaction and a Larmor-type resonance of a quasi-1D Heisenberg system

Interplay between the Dzyaloshinskii-Moriya term and external fields on spin transport in the spin-1/2 one-dimensional antiferromagnet

We study the effect of the uniform Dzyaloshinskii-Moriya interaction (symmetric exchange anisotropy) and arbitrary oriented external magnetic fields on spin conductivity in the spin-1/2 one-dimensional Heisenberg antiferromagnet. The spin conductivity is calculated employing abelian bosonization and the Kubo formalism of transport. We investigate the influence of three competing phases at zero-temperature, (Néel phase, dimerized phase and gapless Luttinger liquid phase) on the AC spin conductivity.

Ising order in a magnetized Heisenberg chain subject to a uniform Dzyaloshinskii-Moriya interaction

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 N\'eel Ising order in the regime of comparable DM and magnetic field magnitudes.

Phase diagram of weakly coupled Heisenberg spin chains subject to a uniform Dzyaloshinskii-Moriya interaction

Motivated by recent experiments on spin chain materials K$_2$CuSO$_4$Cl$_2$ and K$_2$CuSO$_4$Br$_2$, we theoretically investigate the problem of weakly coupled spin chains (chain exchange $J$, interchain $J'$) subject to a $\textit{staggered between chains}$, but $\textit{uniform}$ within a given chain, Dzyaloshinskii-Moriya (DM) interaction of magnitude $D$. In the experimentally relevant limit $J' \ll D \ll J$ of strong DM interaction the spins on the neighboring chains are forced to rotate in opposite directions, effectively resulting in a cancelation of the interchain interaction between components of spins in the plane normal to the vector ${\pmb D}$. This has the effect of promoting two-dimensional collinear spin density wave (SDW) state, which preserves U(1) symmetry of rotations about the $\pmb D$-axis. We also investigate response of this interesting system to an external magnetic field ${\pmb h}$ and obtain the $h-D$ phase diagrams for the two important configurations, ${\pmb h} \parallel {\pmb D}$ and ${\pmb h} \perp {\pmb D}$.

Electron spin resonance in a strong-rung spin-12Heisenberg ladder

Cu(C$_8$H$_6$N$_2$)Cl$_2$, a strong-rung spin-1/2 Heisenberg ladder compound, is probed by means of electron spin resonance (ESR) spectroscopy in the field-induced gapless phase above $H_{c1}$. The temperature dependence of the ESR linewidth is analyzed in the quantum field theory framework, suggesting that the anisotropy of magnetic interactions plays a crucial role, determining the peculiar low-temperature ESR linewidth behavior. In particular, it is argued that the uniform Dzyaloshinskii-Moriya interaction (which is allowed on the bonds along the ladder legs) can be the source of this behavior in Cu(C$_8$H$_6$N$_2$)Cl$_2$.

Electron spin resonance modes in a strong-leg ladder in the Tomonaga-Luttinger liquid phase

Magnetic excitations in the strong-leg quantum spin ladder compound (C$_7$H$_{10}$N)$_2$CuBr$_4$ (known as DIMPY) in the field-induced Tomonaga-Luttinger spin liquid phase are studied by means of high-field electron spin resonance (ESR) spectroscopy. The presence of a gapped ESR mode with unusual non-linear frequency-field dependence is revealed experimentally. Using a combination of analytic and exact diagonalization methods, we compute the dynamical structure factor and identify this mode with longitudinal excitations in the antisymmetric channel. We argue that these excitations constitute a fingerprint of the spin dynamics in a strong-leg spin-1/2 Heisenberg antiferromagnetic ladder and owe its ESR observability to the uniform Dzyaloshinskii-Moriya interaction.

ESR study of the spin ladder with uniform Dzyaloshinskii-Moriya interaction

Evolution of the ESR absorption in a strong-leg spin ladder magnet (C$_7$H$_{10}$N$_2$)$_2$CuBr$_4$ (abbreviated as DIMPY) is studied from 300K to 400mK. Temperature dependence of the ESR relaxation follows a staircase of crossovers between different relaxation regimes. We ague that the main mechanism of ESR line broadening in DIMPY is uniform Dzyaloshinskii-Moria interaction ($|\vec{D}|=0.20$K) with an effective longitudinal component along an exchange bond of Cu ions within the legs resulting from the low crystal symmetry of DIMPY and nontrivial orbital ordering. The same Dzyaloshinskii-Moriya interaction results in the lifting of the triplet excitation degeneracy, revealed through the weak splitting of the ESR absorption at low temperatures.

Approach to control polarization and magnetic properties for multiferroics with Dzyaloshinskii-Moriya interaction

We propose a theoretical model for one-dimensional (charge transfer magnets with Dzyaloshinskii-Moriya (DM) interaction. By using Green's function theory, we have studied the effect of DM interaction on ferroelectric and magnetic properties, where ferroelectricity is induced through symmetric mechanism. It is shown that the uniform DM interaction reduces the polarization and makes the magnetization plateau narrow down. Moreover, the transition temperature descends as the uniform DM interaction ascends, which is attributed to the decrease of the energy gap. In addition, the staggered DM interaction, which is related to intersite distance, is also discussed. It is also found that there exists a critical point, above or below which the staggered DM interaction plays different roles on the polarization, transition temperature, and magnetic behavior. As the staggered DM interaction is larger, it enhances the polarization and transition temperature and meanwhile widens the magnetization plateau, otherwise it reduces the polarization, transition temperature, and magnetization plateau. The results provide approach to control the transition temperature and physical behavior of multiferroics.

Spin correlations and Dzyaloshinskii-Moriya interaction in Cs2CuCl4

We report on electron spin resonance (ESR) studies of the spin relaxation in Cs${}_{2}$CuCl${}_{4}$. The main source of the ESR linewidth at temperatures $T\ensuremath{\le}150$ K is attributed to the uniform Dzyaloshinskii-Moriya interaction. The vector components of the Dzyaloshinskii-Moriya interaction are determined from the angular dependence of the ESR spectra using a high-temperature approximation. Both the angular and temperature dependencies of the ESR linewidth have been analyzed using a self-consistent quantum-mechanical approach. In addition, analytical expressions based on a quasiclassical picture for spin fluctuations are derived, which show good agreement with the quantum-approach for temperatures $T\ensuremath{\ge}2J/{k}_{\mathrm{B}}\ensuremath{\approx}15$ K. A small modulation of the ESR linewidth observed in the $ac$ plane is attributed to the anisotropic Zeeman interaction, which reflects the two magnetically nonequivalent Cu positions.

Temperature dependence of EPR linewidth in one-dimensional magnets: A quasi-classical approach

An analytical expression for the EPR linewidth of an exchange-coupled 1/2-spin chain originating from uniform Dzyaloshinskii-Moriya interaction is derived using a quasi-classical approach. The expression successfully reproduces the results obtained by numerical quantum mechanical calculations based on Green’s function method at T > 2J/kB.

Spatially anisotropic kagome antiferromagnet with Dzyaloshinskii-Moriya interaction

We theoretically study the spatially anisotropic spin-1/2 kagome antiferromagnet with a Dzyaloshinskii-Moriya (DM) interaction using a renormalization-group analysis in the quasi-one-dimensional limit. We identify the various temperature and energy scales for ordering in the system. For a very weak DM interaction, we find a low-temperature spiral phase with the plane of the spiral selected by the DM interaction. This phase is similar to a previously identified phase in the absence of the DM interaction. However, above a critical DM interaction strength we find a transition to a phase with coexisting antiferromagnetic and dimer order, reminiscent of one-dimensional antiferromagnetic systems with a uniform DM interaction. Our results help shed light on the fate of two-dimensional systems with both strong interactions and significant spin-orbit coupling.

Modes of Magnetic Resonance in the Spin-Liquid Phase ofCs2CuCl4

We report the observation of a frequency shift and splitting of the electron spin resonance (ESR) mode of the low-dimensional S=1/2 frustrated antiferromagnet Cs2CuCl4 in the spin-correlated state above the ordering temperature 0.62 K. The shift and splitting exhibit strong anisotropy with respect to the direction of the applied magnetic field and do not vanish in a zero field. The low-temperature evolution of the ESR is a result of the modification of the one-dimensional spinon continuum by the uniform Dzyaloshinskii-Moriya interaction within the spin chains.

Interplay between symmetric exchange anisotropy, uniform Dzyaloshinskii-Moriya interaction, and magnetic fields in the phase diagram of quantum magnets and superconductors

We theoretically study the joint influence of uniform Dzyaloshinskii-Moriya (DM) interactions, symmetric exchange anisotropy (with its axis parallel to the DM vector) and arbitrarily oriented magnetic fields on one-dimensional spin 1/2 antiferromagnets. We show that the zero-temperature phase diagram contains three competing phases: (i) an antiferromagnet with Neel vector in the plane spanned by the DM vector and the magnetic field, (ii) a {\em dimerized} antiferromagnet with Neel vector perpendicular to both the DM vector and the magnetic field, and (iii) a gapless Luttinger liquid. Phase (i) is destroyed by a small magnetic field component along the DM vector and is furthermore unstable beyond a critical value of easy-plane anisotropy, which we estimate using Abelian and non-Abelian bosonization along with perturbative renormalization group. We propose a mathematical equivalent of the spin model in a one-dimensional Josephson junction (JJ) array located in proximity to a bulk superconductor. We discuss the analogues of the magnetic phases in the superconducting context and comment on their experimental viability.

Spin-orbital effects in magnetized quantum wires and spin chains

We present analysis of the interacting quantum wire problem in the presence of magnetic field and spin-orbital interaction. We show that an interesting interplay of Zeeman and spin-orbit terms, facilitated by the electron-electron interaction, results in the spin-density wave (SDW) state when the magnetic-field and spin-orbit axes are orthogonal. We show that this instability is enhanced in a closely related problem of Heisenberg spin chain with asymmetric uniform Dzyaloshinskii-Moriya (DM) interaction. Magnetic field in the direction perpendicular to the DM anisotropy axis results in staggered long-range magnetic order along the orthogonal to the applied field direction. We explore consequences of the uniform DM interaction for the electron-spin-resonance (ESR) measurements, and point out that they provide way to probe right- and left-moving excitations of the spin chain separately.