Quantum spin liquid and magnetic order in a two-dimensional nonsymmorphic lattice: Considering the distorted kagome lattice of volborthite

Chern, Li Ern; Hwang, Kyusung; Mizoguchi, Tsuyoshi; Huh, Young Eun; Kim, Yong Baek

doi:10.1103/physrevb.96.035118

Cited by 6 publications

(3 citation statements)

References 36 publications

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“…While no clear non-zero κ 0 /T term was observed for Volborthite due to its relatively high ordering temperature, the estimated mean free path of the spin excitations from the 8 K magnetic thermal conductivity is about 80 times its inter-spin distance, which indicates its spin excitations are highly mobile 49 . The related theoretical work also proposes the existence of spinon Fermi surface in Volborthite above T N 50,51 . Another relevant example is pyrochlore Yb 2 Ti 2 O 7 with effective spin-1/2 Yb 3+ ions, which ferromagnetically orders at T C~0 .2 K 52 .…”

Section: Resultsmentioning

confidence: 97%

Possible itinerant excitations and quantum spin state transitions in the effective spin-1/2 triangular-lattice antiferromagnet Na2BaCo(PO4)2

Huang

Yue

et al. 2020

Nat Commun

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The most fascinating feature of certain two-dimensional (2D) gapless quantum spin liquid (QSL) is that their spinon excitations behave like the fermionic carriers of a paramagnetic metal. The spinon Fermi surface is then expected to produce a linear increase of the thermal conductivity with temperature that should manifest via a residual value (κ 0 /T) in the zerotemperature limit. However, this linear in T behavior has been reported for very few QSL candidates. Here, we studied the ultralow-temperature thermal conductivity of an effective spin-1/2 triangular QSL candidate Na 2 BaCo(PO 4) 2 , which has an antiferromagnetic order at very low temperature (T N~1 48 mK), and observed a finite κ 0 /T extrapolated from the data above T N. Moreover, while approaching zero temperature, it exhibits series of quantum spin state transitions with applied field along the c axis. These observations indicate that Na 2 BaCo (PO 4) 2 possibly behaves as a gapless QSL with itinerant spin excitations above T N and its strong quantum spin fluctuations persist below T N .

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Section: Resultsmentioning

confidence: 97%

Possible itinerant excitations and quantum spin state transitions in the effective spin-1/2 triangular-lattice antiferromagnet Na2BaCo(PO4)2

Huang

Yue

et al. 2020

Nat Commun

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“…where the elementary triangles that build up the kagome lattice are no longer equilateral but isosceles, leading to different antiferromagnetic couplings along short and long bonds. In this case, there is some evidence for a magnetic ground state, even though unusually slow spin fluctuations persist down to low temperatures [25][26][27][28][29][30][31][32][33]. Another interesting deformation is one leading to alternately sized equilateral triangles, dubbed the trimerized or breathing kagome lattice [34], in analogy to the breathing pyrochlores [35].…”

Section: Introductionmentioning

confidence: 99%

Persistence of the gapless spin liquid in the breathing kagome Heisenberg antiferromagnet

et al. 2018

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The nature of the ground state of the spin S = 1/2 Heisenberg antiferromagnet on the kagome lattice with breathing anisotropy (i.e., with different superexchange couplings J and J within elementary up-and downpointing triangles) is investigated within the framework of Gutzwiller projected fermionic wave functions and Monte Carlo methods. We analyze the stability of the U(1) Dirac spin liquid with respect to the presence of fermionic pairing that leads to a gapped Z2 spin liquid. For several values of the ratio J /J , the size scaling of the energy gain due to the pairing fields and the variational parameters are reported. Our results show that the energy gain of the gapped spin liquid with respect to the gapless state either vanishes for large enough system size or scales to zero in the thermodynamic limit. Similarly, the optimized pairing amplitudes (responsible for opening the spin gap) are shown to vanish in the thermodynamic limit. Our outcome is corroborated by the application of one and two Lanczos steps to the gapless and gapped wave functions, for which no energy gain of the gapped state is detected when improving the quality of the variational states. Finally, we discuss the competition with the "simplex" Z2 resonating-valence-bond spin liquid, valence-bond crystal, and nematic states in the strongly anisotropic regime, i.e., J J .arXiv:1712.04579v2 [cond-mat.str-el] 15 Mar 2018 J /J = 1 J /J = 0.9 J /J = 0.7 J /J = 0.5 J /J = 0.3 J /J = 0.1 Z of J ) in the strong anisotropy limit:FIG. 7. For different values of the breathing anisotropy J /J , the finite-size scaling of the energy gain (in units of J ) of the sixsite unit-cell VBC with respect to the U(1) Dirac spin liquid, i.e., [E(VBC)−E(U(1))]/J . The clusters considered are L = 8, 12, 16, and 20.

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“…This can provide a scenario for Phase N (or N 2 ) observed experimentally [55]. The coupled-trimer model has also stimulated theoretical studies of possible QSLs above magnetic ordering temperatures [56,57].…”

Section: Introductionmentioning

confidence: 99%

Effects of Dzyaloshinskii–Moriya Interactions in Volborthite: Magnetic Orders and Thermal Hall Effect

Furukawa

Momoi

2020

J. Phys. Soc. Jpn.

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Volborthite offers an interesting example of a highly frustrated quantum magnet in which ferromagnetic and antiferromagnetic interactions compete on anisotropic kagome lattices. A recent density functional theory calculation has provided a magnetic model based on coupled trimers, which is consistent with a broad 1 3 -magnetization plateau observed experimentally. Here we study the effects of Dzyaloshinskii-Moriya (DM) interactions in volborthite. We derive an effective model in which pseudospin-1 2 moments emerging on trimers form a network of an anisotropic triangular lattice. Using the effective model, we show that for a magnetic field perpendicular to the kagome layer, magnon excitations from the 1 3 -plateau feel a Berry curvature due to the DM interactions, giving rise to a thermal Hall effect. Our magnon Bose gas theory can explain qualitative features of the magnetization and the thermal Hall conductivity measured experimentally. A further quantitative comparison with experiment poses constraints on the coupling constants in the effective model, promoting a quasi-one-dimensional picture. Based on this picture, we analyze low-temperature magnetic phase diagrams using effective field theory, and point out their crucial dependence on the field direction. arXiv:1909.09425v1 [cond-mat.str-el] 20 Sep 2019and for r ∈ B by H r,r+u =J 1 S r,1 · S r+u,1 + J S r,2 · S r+u,1 − D 1 · (S r,1 × S r+u,1 ) − D · (S r,2 × S r+u,1 ), H r,r+v =J 1 S r,3 · S r+v,3 + J S r,3 · S r+v,2 +D 1 · (S r,3 × S r+v,3 ) +D · (S r,3 × S r+v,2 ).Furthermore, the inter-trimer interactions along b are given for r ∈ X = A, B by H r,r+b =J 2 (S r,1 · S r+b,1 + S r,3 · S r+b,3 ) − D 2X · (S r,1 × S r+b,1 − S r,3 × S r+b,3 )

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Quantum spin liquid and magnetic order in a two-dimensional nonsymmorphic lattice: Considering the distorted kagome lattice of volborthite

Cited by 6 publications

References 36 publications

Possible itinerant excitations and quantum spin state transitions in the effective spin-1/2 triangular-lattice antiferromagnet Na2BaCo(PO4)2

Possible itinerant excitations and quantum spin state transitions in the effective spin-1/2 triangular-lattice antiferromagnet Na2BaCo(PO4)2

Persistence of the gapless spin liquid in the breathing kagome Heisenberg antiferromagnet

Effects of Dzyaloshinskii–Moriya Interactions in Volborthite: Magnetic Orders and Thermal Hall Effect

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