One-dimensional spin liquid, collinear, and spiral phases from uncoupled chains to the triangular lattice

Tocchio, Luca F.; Gros, Claudius; Valentí, Roser; Becca, Federico

doi:10.1103/physrevb.89.235107

Cited by 38 publications

(47 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Finally, we present charge susceptibilities in different areas of parameter space, which should correspond to momentum-resolved electron-loss spectroscopy measurements on triangular compounds., suggests that these compounds are close to a two-dimensional triangular structure and exhibit interesting electron correlation behavior including, potentially, a quantum spin liquid phase [7] in the ground state [8]. These compounds, as well as the low energy physics of the fully isotropic triangular material Ba 8 CoNb 6 O 24 [9], may be described by a half-filled single orbital Hubbard model on a triangular two-dimensional lattice, with an on-site Coulomb interaction strength comparable to or larger than the bandwidth [10].Because of the subtle competition of metallic, ordered, and spin liquid phases in the ground state, this model has been studied extensively with a wide range of numerical tools, including exact diagonalization (ED) [11][12][13], density matrix renormalization group theory (DMRG) [8], variational Monte Carlo (VMC) [14][15][16][17], variational cluster approximation [18][19][20], strong coupling expansions [21], path integral renormalization group techniques [22], and cluster dynamical mean field theory (DMFT) in the cellular [23][24][25][26][27] and dynamical cluster [28,29] variants. The focus in most of these studies has been on the precise location of the phase boundaries, ordering (or the absence thereof), and on the nature of these phases.Experimentally, much of our knowledge about correlated triangular systems is obtained from single-and two-particle scattering experiments such as photoemission [30], Raman spectroscopy [31], nuclear magnetic resonance (NMR) [2,32], or inelastic neutron scattering [9,33].…”

mentioning

confidence: 99%

“…Because of the subtle competition of metallic, ordered, and spin liquid phases in the ground state, this model has been studied extensively with a wide range of numerical tools, including exact diagonalization (ED) [11][12][13], density matrix renormalization group theory (DMRG) [8], variational Monte Carlo (VMC) [14][15][16][17], variational cluster approximation [18][19][20], strong coupling expansions [21], path integral renormalization group techniques [22], and cluster dynamical mean field theory (DMFT) in the cellular [23][24][25][26][27] and dynamical cluster [28,29] variants. The focus in most of these studies has been on the precise location of the phase boundaries, ordering (or the absence thereof), and on the nature of these phases.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Magnetic and charge susceptibilities in the half-filled triangular lattice Hubbard model

Gull

2020

Phys. Rev. Research

View full text Add to dashboard Cite

We study magnetic and charge susceptibilities in the half-filled two-dimensional triangular Hubbard model within the dual fermion approximation in the metallic, Mott insulating, and crossover regions of parameter space. In the insulating state, we find strong spin fluctuations at the K point at low energy corresponding to the 120 • antiferromagnetic order. These spin fluctuations persist into the metallic phase and move to higher energy. We also present data for simulated neutron spectroscopy and spin-lattice relaxation times, and perform direct comparisons to inelastic neutron spectroscopy experiments on the triangular material Ba8CoNb6O24 and to the relaxation times on κ-(ET)2Cu2(CN)3. Finally, we present charge susceptibilities in different areas of parameter space, which should correspond to momentum-resolved electron-loss spectroscopy measurements on triangular compounds., suggests that these compounds are close to a two-dimensional triangular structure and exhibit interesting electron correlation behavior including, potentially, a quantum spin liquid phase [7] in the ground state [8]. These compounds, as well as the low energy physics of the fully isotropic triangular material Ba 8 CoNb 6 O 24 [9], may be described by a half-filled single orbital Hubbard model on a triangular two-dimensional lattice, with an on-site Coulomb interaction strength comparable to or larger than the bandwidth [10].Because of the subtle competition of metallic, ordered, and spin liquid phases in the ground state, this model has been studied extensively with a wide range of numerical tools, including exact diagonalization (ED) [11][12][13], density matrix renormalization group theory (DMRG) [8], variational Monte Carlo (VMC) [14][15][16][17], variational cluster approximation [18][19][20], strong coupling expansions [21], path integral renormalization group techniques [22], and cluster dynamical mean field theory (DMFT) in the cellular [23][24][25][26][27] and dynamical cluster [28,29] variants. The focus in most of these studies has been on the precise location of the phase boundaries, ordering (or the absence thereof), and on the nature of these phases.Experimentally, much of our knowledge about correlated triangular systems is obtained from single-and two-particle scattering experiments such as photoemission [30], Raman spectroscopy [31], nuclear magnetic resonance (NMR) [2,32], or inelastic neutron scattering [9,33]. To understand these experimental results, it is necessary to calculate the corresponding response functions as a function of energy and momentum. For neutron spectroscopy and angular-resolved photoemission spectroscopy, in particular, both fine momentum and energy resolutions are desired. Such results are difficult to obtain, as computational methods formulated on finite lattices (such as ED, DMRG, and cluster DMFT) pro-

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

Magnetic and charge susceptibilities in the half-filled triangular lattice Hubbard model

Gull

2020

Phys. Rev. Research

View full text Add to dashboard Cite

show abstract

“…But, U eff cancels from the ratio of superexchange parameters, e.g., J SE B /J SE y ∼ 2t 2 B /(t 2 r + t 2 S ), allowing this to be calculated. The values in Table II 3) which gives rise to a gapless spin-liquid state [6][7][8][9][10][11].…”

Section: Supplementary Informationmentioning

confidence: 99%

Frustration, ring exchange, and the absence of long-range order inEtMe3Sb[Pd(dmit)2]2: From first principles to many-body theory

Kenny

David

Ferré

et al. 2020

Phys. Rev. Materials

View full text Add to dashboard Cite

We parameterize Hubbard and thence spin models for EtMe3Sb[Pd(dmit)2]2 from broken symmetry density functional calculations. This gives a scalene triangular model where the largest net exchange interaction is three times larger than the mean interchain coupling. The chain random phase approximation shows that the difference in the interchain couplings is equivalent to a bipartite interchain coupling, favoring long-range magnetic order. This competes with ring exchange, which favors quantum disorder. Ring exchange wins.EtMe 3 Sb[Pd(dmit) 2 ] 2 (EtMe 3 Sb) is a quantum spin liquid (QSL) candidate shrouded in mystery. It lacks magnetic ordering down to the lowest temperatures measured [1-3], but the physics that results in a quantum disordered state remains under debate. EtMe 3 Sb shares important structural motifs with the quantum spin liquids κ-(BEDT-TTF) 2 Cu 2 (CN) 3 (κ-Cu) and κ-(BEDT-TTF) 2 Ag 2 (CN) 3 (κ-Ag). A crucial question is: how closely related are their ground states?EtMe 3 Sb, κ-Cu, and κ-Ag all form structures with alternating layers of organic molecules and counter-ions. In all three materials, the organic molecules dimerize with one unpaired electron found on each dimer in the insulating phase. The main structural difference between them is the spacial arrangement the dimers. Within κ-Cu and κ-Ag, neighboring dimers are almost perpendicular to one another, whereas in EtMe 3 Sb, the dimers (gray circles in Fig. 1a) form quasi-onedimensional stacks (along the horizontal in Fig. 1a).κ-Cu and κ-Ag are Mott insulators. In the strong coupling limit, where the Hubbard U is much greater than the largest interdimer hopping integral, t, their insulating phase is described by the isosceles triangular Heisenberg model (Fig. 1c). This model has two candidate QSL phases. Firstly, a QSL has been suggested in the region 0.6 J /J 0.9 [4-6], for which the ground state remains controversial. Secondly, the large J /J limit is adiabatically connected to the Tomonaga-Luttinger liquid (TLL) expected for uncoupled chains, J /J 1.4 [6][7][8][9][10][11]. Theories in this regime show an emergent 'one-dimensionalization' whereby the many-body state is more one-dimensional than the underlying Hamiltonian [12][13][14][15]. However, the validity of the strong coupling limit in these materials is uncertain because both materials undergo a Mott metal-insulator transition under moderate pressures. This motivates the inclusion of higher order terms, most importantly ring exchange, in the spin model. It has been shown that these can also cause QSL phases [16][17][18][19][20].Many early studies explored the possibility that the spin liquid in EtMe 3 Sb can be explained by one of the above theories. However, the lower symmetry of EtMe 3 Sb means that all three exchange interactions are different, i.e., it is described by a scalene triangular lattice, Fig. 1a,b. EtMe 3 Sb is also close to a Mott transition and so ring exchange is likely to be important.

show abstract

“…The presence of this phase is not surprising since different studies predict the appearance of this magnetic phase in the M1d regime using lattice models 30,31 or spin models. 36,39,40,59 At this magnetic transition, we observe a jump in the double-occupancy and a gap opening in the spectral function.…”

Section: B Magnetic Statesmentioning

confidence: 99%

Mott transition and magnetism on the anisotropic triangular lattice

et al. 2016

View full text Add to dashboard Cite

Spin-liquid behavior was recently suggested experimentally in the moderately one-dimensional organic compound κ-H3(Cat-EDT-TTF)2. This compound can be modeled by the one-band Hubbard model on the anisotropic triangular lattice with t /t 1.5, where t is the minority hopping. It thus becomes important to extend previous studies, that were performed in the range 0 ≤ t /t ≤ 1.2, to find out whether there is a regime where Mott insulating behavior can be found without longrange magnetic order. To this end, we study the above model in the range 1.2 ≤ t /t ≤ 2 using cluster dynamical mean-field theory (CDMFT). We argue that it is important to choose a symmetrypreserving cluster rather than a quasi one-dimensional cluster. We find that, upon increasing t /t beyond t /t ≈ 1.3, the Mott transition at zero-temperature is replaced by a first-order transition separating a metallic state from a collinear magnetic insulating state. Nevertheless, at the physically relevant value t /t 1.5, the transitions toward the magnetic and the Mott insulating phases are very close. The phase diagram obtained in this study can provide a working basis for moderately one-dimensional compounds on the anisotropic triangular lattice.

show abstract

One-dimensional spin liquid, collinear, and spiral phases from uncoupled chains to the triangular lattice

Cited by 38 publications

References 56 publications

Magnetic and charge susceptibilities in the half-filled triangular lattice Hubbard model

Magnetic and charge susceptibilities in the half-filled triangular lattice Hubbard model

Frustration, ring exchange, and the absence of long-range order inEtMe3Sb[Pd(dmit)2]2: From first principles to many-body theory

Mott transition and magnetism on the anisotropic triangular lattice

Contact Info

Product

Resources

About