Quantum phase transitions in the Heisenberg<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>J</mml:mi><mml:mn>1</mml:mn></mml:msub><mml:mo>−</mml:mo><mml:msub><mml:mi>J</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>triangular antiferromagnet in a magnetic field

Ye, Mengxing; Chubukov, Andrey V.

doi:10.1103/physrevb.95.014425

Cited by 21 publications

(20 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In NaYbO 2 , external magnetic field triggers long-range order above 2 T with an up-up-down spin pattern [146] typical of the 1 3 -plateau phase of triangular antiferromagnets. In the fully isotropic (Heisenberg) case, this up-updown phase occurs only at J 2 /J 1 < 0.125 [150,151] suggesting that J 2 /J 1 should be lower than in YbMgGaO 4 , in agreement with the fact that the absolute value of J 1 increases.…”

Section: Other 4f Materialsmentioning

confidence: 56%

“…First, with the exception of Ba 3 CoSb 2 O 9 field-induced behavior is largely unknown, and even theory studies of the anisotropic J 1 − J 2 Hamiltonians in the applied field remain scarce [150,151]. NaYbO 2 shows a quite unusual transition between the spin-liquid phase in zero field and the collinear up-up-down phase in the applied field [145,146] (a similar transformation was claimed in randomness-influenced YbMgGaO 4 too [166]).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Spin liquids in geometrically perfect triangular antiferromagnets

Gegenwart

Tsirlin

2020

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

The cradle of quantum spin liquids, triangular antiferromagnets show strong proclivity to magnetic order and require deliberate tuning to stabilize a spin-liquid state. In this brief review, we juxtapose recent theoretical developments that trace the parameter regime of the spin-liquid phase, with experimental results for Co-based and Yb-based triangular antiferromagnets. Unconventional spin dynamics arising from both ordered and disordered ground states is discussed, and the notion of a geometrically perfect triangular system is scrutinized to demonstrate non-trivial imperfections that may assist magnetic frustration in stabilizing dynamic spin states with peculiar excitations.

show abstract

Section: Other 4f Materialsmentioning

confidence: 56%

Section: Discussionmentioning

confidence: 99%

Spin liquids in geometrically perfect triangular antiferromagnets

Gegenwart

Tsirlin

2020

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

show abstract

“…This plateau has been observed in Cs 2 CuBr 4 [13][14][15][16][17] and in Ba 3 CoSb 2 O 9 [18]. An UUD state survives in a finite range of perturbations, like the spatial anisotropy of the exchange interaction [10][11][12][19][20][21][22], multiple-spin ring exchange [23], and the next nearest neighbor exchange [24], as long as the perturbations are not strong enough to close the minimal excitation gap in the UUD state. What replaces the UUD state at larger perturbations has been the subject of intensive research over the last several years [10-12, 20-22, 25-28]…”

Section: Introductionmentioning

confidence: 87%

“…6. Though different from the fully polarized state [6,24], the quadratic Hamiltonian of the UUUD state gets corrections from quantum fluctuations, the calculation can be self-consistently carried out in powers of 1/S. For our purpose, it is enough to calculate K up to order 1/S.…”

Section: Corrections From Quantum Fluctuationsmentioning

confidence: 99%

Half-magnetization plateau in a Heisenberg antiferromagnet on a triangular lattice

Chubukov

2017

Phys. Rev. B

Self Cite

View full text Add to dashboard Cite

We present the phase diagram in a magnetic field of a 2D isotropic Heisenberg antiferromagnet on a triangular lattice. We consider spin-S model with nearest-neighbor (J1) and next-nearest-neighbor (J2) interactions. We focus on the range of 1/8 < J2/J1 < 1, where the ordered states are different from those in the model with only nearest neighbor exchange. A classical ground state in this range has four sublattices and is infinitely degenerate in any field. The actual order is then determined by quantum fluctuations via "order from disorder" phenomenon. We argue that the phase diagram is rich due to competition between competing four-sublattice quantum states which break either Z3 orientational symmetry or Z4 sublattice symmetry. At small and high fields, the ground state is a Z3-breaking canted stripe state, but at intermediate fields the ordered states break Z4 sublattice symmetry. The most noticeable of such states is "three up, one down" state in which spins in three sublattices are directed along the field and in one sublattice opposite to the field. Such a state breaks no continuous symmetry and has gapped excitations. As the consequence, magnetization has a plateau at exactly one half of the saturation value. We identify gapless states, which border the "three up, one down" state and discuss the transitions between these states and the canted stripe state. IntroductionRecent experimental and theoretical advances renewed the interest in the physics of frustrated spin systems. In many of these systems the classical ground state is infinitely degenerate, and the actual ground state spin configuration is selected by quantum fluctuations (the "order from disorder" phenomenon). The resulting ground state is often rather unconventional and in several cases displays a non-monotonic behavior of magnetization in an applied field, with kinks, jumps, and plateaus [1][2][3][4][5][6][7]. The most known example of such behavior is in the case of a two-dimensional (2D) quantum antiferromagnet on a triangular lattice with nearestneighbor exchange J 1 [8,9]. Classically, all spin configurations, which satisfy S r + S r+δ1 + S r+δ2 = hS/(3J 1 ) for each triad of neighboring spins, have the same ground state energy. Quantum fluctuations lift the degeneracy and select a set of three coplanar configurations, between which the systems transforms upon increasing field. The middle configuration, which exists at h around 1/3 of the saturation field h sat = 9J 1 (h scaled), is a collinear state with two spins up (U) and one spin down (D) in every elementary triangle (an UUD state). In such a state only a discrete Z 3 symmetry is broken (one spin in a triad is selected to be antiparallel to a field), and, as a result, all excitations are gapped and the magnetization has a plateau at exactly one-third of the saturation value [8][9][10][11][12]. This plateau has been observed in Cs 2 CuBr 4 [13][14][15][16][17] and in Ba 3 CoSb 2 O 9 [18]. An UUD state survives in a finite range of perturbations, like the spatial anisotropy of the exch...

show abstract

“…The presence of multiple phase transitions and magnetization plateaus in a moderate magnetic field [76] is expected in the case of a XXZ triangular-lattice antiferromagnet [77,78]. This may also help to constrain the possible values of J 2 [79] and anisotropic exchanges, although exchange disorder may be very efficient at suppressing these features [80]. Because of their nonspin-conserving nature, dominant pseudodipolar interactions should manifest as an asymptotic approach to saturated magnetization, as recently observed in the candidate Kitaev spin liquid α-RuCl 3 [81].…”

Section: Discussionmentioning

confidence: 99%

Hierarchy of Exchange Interactions in the Triangular-Lattice Spin Liquid YbMgGaO4

et al. 2018

View full text Add to dashboard Cite

The spin-1=2 triangular lattice antiferromagnet YbMgGaO 4 has attracted attention recently as a quantum spin-liquid candidate with the possible presence of off-diagonal anisotropic exchange interactions induced by spin-orbit coupling. Whether a quantum spin liquid is stabilized or not depends on the interplay of various exchange interactions with chemical disorder that is inherent to the layered structure of the compound. We combine time-domain terahertz spectroscopy and inelastic neutron scattering measurements in the field-polarized state of YbMgGaO 4 to obtain better insight of its exchange interactions. Terahertz spectroscopy in this fashion functions as a high-field electron spin resonance and probes the spin-wave excitations at the Brillouin zone center, ideally complementing neutron scattering. A global spin-wave fit to all our spectroscopic data at fields over 4 T, informed by the analysis of the terahertz spectroscopy linewidths, yields constraints on the disorder-averaged g factors and exchange interactions. Our results paint YbMgGaO 4 as an easy-plane XXZ antiferromagnet with the combined and necessary presence of subleading next-nearest neighbor and weak anisotropic off-diagonal nearest-neighbor interactions. Moreover, the obtained g factors are substantially different from previous reports. This work establishes the hierarchy of exchange interactions in YbMgGaO 4 from high-field data alone and thus strongly constrains possible mechanisms responsible for the observed spin-liquid phenomenology.

show abstract

Quantum phase transitions in the HeisenbergJ1−J2triangular antiferromagnet in a magnetic field

Cited by 21 publications

References 46 publications

Spin liquids in geometrically perfect triangular antiferromagnets

Spin liquids in geometrically perfect triangular antiferromagnets

Half-magnetization plateau in a Heisenberg antiferromagnet on a triangular lattice

Hierarchy of Exchange Interactions in the Triangular-Lattice Spin Liquid YbMgGaO4

Contact Info

Product

Resources

About