Spin chirality on a two-dimensional frustrated lattice

Grohol, Daniel; Matan, K.; Cho, Jin-Hyung; Lee, Seunghun; Lynn, J. W.; Nocera, Daniel G.; Lee, Young S.

doi:10.1038/nmat1353

Cited by 271 publications

(280 citation statements)

References 30 publications

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“…The low-temperature dependence of κ xy for the present model is plotted in Fig. 5(a) with the parameter values of KFe 3 (OH) 6 (SO 4 ) 2 [31]. At zero magnetic field there is no thermal Hall effect in accordance with the analysis of topological spin waves and edge modes discussed above.…”

Section: Arxiv:160804561v12 [Cond-matstr-el] 16 Jan 2017supporting

confidence: 79%

“…Hence, the DMI suppresses the QSL phase of frustrated kagomé antiferromagnets up to a critical value [30]. The syntheses of materials have shown that various experimentally accessible frustrated kagomé antiferromagnets show evidence of coplanar/noncollinear q = 0 LRO at specific temperatures [29][30][31][32][33][34] [36] are fragile in the presence of applied magnetic field or pressure and they show evidence of LRO [37,38]. However, the role of DMI and magnetic field in frustrated kagome magnets has not been investigated in the context of thermal Hall effect and topological spin excitations.…”

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confidence: 99%

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Topological thermal Hall effect in frustrated kagome antiferromagnets

Owerre

2017

Phys. Rev. B

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In frustrated magnets the Dzyaloshinsky-Moriya interaction (DMI) arising from spin-orbit coupling (SOC) can induce a magnetic long-range order. Here, we report a theoretical prediction of thermal Hall effect in frustrated kagomé magnets such as KCr3(OH)6(SO4)2 and KFe3(OH)6(SO4)2. The thermal Hall effects in these materials are induced by scalar spin chirality as opposed to DMI in previous studies. The scalar spin chirality originates from magnetic-field-induced chiral spin configuration due to non-coplanar spin textures, but in general it can be spontaneously developed as a macroscopic order parameter in chiral quantum spin liquids. Therefore, we infer that there is a possibility of thermal Hall effect in frustrated kagomé magnets such as herbertsmithite ZnCu3(OH)6Cl2 and the chromium compound Ca10Cr7O28, although they also show evidence of magnetic long-range order in the presence of applied magnetic field or pressure.Introduction-. Topological phases of matter are an active research field in condensed matter physics, mostly dominated by electronic systems. Quite recently the concepts of topological matter have been extended to nonelectronic bosonic systems such as quantized spin waves (magnons) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] and quantized lattice vibrations (phonons) [18][19][20][21][22][23]. In the former, spin-orbit coupling manifests in the form of Dzyaloshinsky-Moriya interaction [24,25] and it leads to topological spin excitations and chiral edge modes in collinear ferromagnets [5,6]. The quantized spin waves or magnons are charge-neutral quasiparticles and they do not experience a Lorentz force as in charge particles. However, a temperature gradient can induce a heat current and the DMI-induced Berry curvature acts as an effective magnetic field in momentum space. This leads to a thermal version of the Hall effect characterized by a temperature dependent thermal Hall conductivity [1,3]. Thermal Hall effect is now an emerging active research area for probing the topological nature of magnetic spin excitations in quantum magnets. The thermal Hall effect of spin waves has been realized experimentally in a number of pyrochlore ferromagnets [2,4]. Recently, DMI-induced topological magnon bands and thermal Hall effect have been observed in collinear kagomé ferromagnet Cu(1-3, bdc) [8,9].In frustrated kagomé magnets, however, there is no magnetic long-range order (LRO) down to the lowest accessible temperatures. The classical ground states have an extensive degeneracy and they are considered as candidates for quantum spin liquid (QSL) [26,27]. The ground state of spin-1/2 Heisenberg model on the kagomé lattice is believed to be a U(1)-Dirac spin liquid [28]. In physical realistic materials, however, there are other interactions and perturbations that tend to alleviate QSL ground states and lead to LRO. Recent experimental syntheses of kagomé antiferromagnetic materials have shown that the effects of SOC or DMI are not negligible in frustrated magnets. The DMI is an intrinsic pertur...

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Section: Arxiv:160804561v12 [Cond-matstr-el] 16 Jan 2017supporting

confidence: 79%

mentioning

confidence: 99%

Topological thermal Hall effect in frustrated kagome antiferromagnets

Owerre

2017

Phys. Rev. B

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“…This is in agreement with our finding that the thermal evolution of the single-crystal X-ray diffraction intensity of corresponding (0 2n+1 0) peaks is best fit with a critical exponent belonging to the 3D universality class. Although well-described by 2D theory in its low-pressure singlet phase, antiferromagnetic SCBO at high pressure supports the well-known Mermin-Wagner theorem (21,22) that long-range order can only survive fluctuations in three dimensions (23,24), and joins geometrically frustrated chiral magnets [25][26][27][28][29] in underscoring the importance of the DM interaction to the formation of exotic magnetic ground states.…”

Section: Significancementioning

confidence: 61%

Emergence of long-range order in sheets of magnetic dimers

Haravifard

Banerjee

Wezel

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Quantum spins placed on the corners of a square lattice can dimerize and form singlets, which then can be transformed into a magnetic state as the interactions between dimers increase beyond threshold. This is a strictly 2D transition in theory, but real-world materials often need the third dimension to stabilize long-range order. We use high pressures to convert sheets of Cu 2+ spin 1/2 dimers from local singlets to global antiferromagnet in the model system SrCu 2 (BO 3 ) 2 . Single-crystal neutron diffraction measurements at pressures above 5 GPa provide a direct signature of the antiferromagnetic ordered state, whereas high-resolution neutron powder and X-ray diffraction at commensurate pressures reveal a tilting of the Cu spins out of the plane with a critical exponent characteristic of 3D transitions. The addition of anisotropic, interplane, spin-orbit terms in the venerable Shastry-Sutherland Hamiltonian accounts for the influence of the third dimension.condensed matter physics | quantum magnetism | phase transition | dimensional cross-over | neutron and X-ray scattering T wo-dimensional systems lie at the boundary between the order-destroying effects of fluctuations in lower dimension and the emergence of true long-range order in higher dimension. How ordered states form and remain stable at finite temperature is a fundamental question that cuts across the sciences. In physics, surfaces, quantum wells, and layered compounds all have provided insights into the peculiar nature of 2D phases, phase transitions, and dimensional cross-over effects. Of particular interest for quantum phase transitions is the theoretically tractable case of interacting magnetic spins placed on a 2D square lattice, the Shastry-Sutherland model (1). The geometry prevents simultaneous satisfaction of all spin-spin coupling terms, leading to a frustrated state that in turn enhances the effects of quantum fluctuations. As the coupling terms are tuned, magnetic order can emerge, but its nature and the potential influence of other sheets of spins in a real physical system have not been probed directly.The Shastry-Sutherland model can be described by the Hamiltonian:where a set of S = 1/2 spins sits on a square lattice and interacts via a regular array of diagonal bonds. This creates a network of dimers with antiferromagnetic intradimer coupling J and interdimer coupling J′. The ground state depends on the ratio of J′=J = x. For x < 0.7, the ground state consists of S = 0 singlets, whereas for x > 0.9 a global antiferromagnetic phase is expected.For intermediate values of x, a variety of locally ordered states has been predicted (2). The first known experimental realization of the ShastrySutherland lattice is SrCu 2 (BO 3 ) 2 (SCBO) (3). The magnetism in SCBO consists of S = 1/2 Cu 2+ ions in well-separated planes whose nearest-neighbor interactions are mediated by in-plane oxygen bonds; layered Cu-O compounds of this kind are of broad interest due to their role in driving phenomena such as high-temperature superconductivity. At ambient...

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“…The crystal structure of the -phase has been identified as rhombohedral c R3 in [28], tetragonal in [29], cubic mcm I / 4 m Pm3 in [30], monoclinic m P 1 2 or m C 2 in [31], and, recently, as orthorhombic Pbnm in [32]. The change of structure, loss of magnetic order and metallization of BiFeO 3 are also observed under pressure of [45][46][47][48][49][50][51][52][53][54][55] GPa at room temperature [33][34][35][36].…”

Section: Introductionmentioning

confidence: 99%

Magnetoelectric Ordering of BiFeO3 from the Perspective of Crystal Chemistry

Волкова

Marinin

2011

J Supercond Nov Magn

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In this paper we examine the role of crystal chemistry factors in creating conditions for formation of magnetoelectric ordering in BiFeO 3 . It is generally accepted that the main reason of the ferroelectric distortion in BiFeO 3 is concerned with a stereochemical activity of the Bi lone pair. However, the lone pair is stereochemically active in the paraelectric orthorhombic ß-phase as well. We demonstrate that a crucial role in emerging of phase transitions of the metal-insulator, paraelectric-ferroelectric and magnetic disorder-order types belongs to the change of the degree of the lone pair stereochemical activity -its consecutive increase with the temperature decrease. Using the structural data, we calculated the sign and strength of magnetic couplings in BiFeO 3 in the range from 945º down to 25º С and found the couplings, which undergo the antiferromagneticferromagnetic transition with the temperature decrease and give rise to the antiferromagnetic ordering and its delay in regard to temperature, as compared to the ferroelectric ordering. We discuss the reasons of emerging of the spatially modulated spin structure and its suppression by doping with La 3+ .

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Spin chirality on a two-dimensional frustrated lattice

Cited by 271 publications

References 30 publications

Topological thermal Hall effect in frustrated kagome antiferromagnets

Topological thermal Hall effect in frustrated kagome antiferromagnets

Emergence of long-range order in sheets of magnetic dimers

Magnetoelectric Ordering of BiFeO3 from the Perspective of Crystal Chemistry

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