Frustration-Induced Insulating Chiral Spin State in Itinerant Triangular-Lattice Magnets

Kumar, Sanjeev; Brink, Jeroen van den

doi:10.1103/physrevlett.105.216405

Cited by 67 publications

(91 citation statements)

References 41 publications

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“…In noncoplanar spin configuration, the density of states and the resistivity at quarter filling are independent of the temperature, while the system undergoes a metal-insulator transition when J AF increases [10]. Furthermore, the bad metallic behavior is consistent with experimental observation in frustrated itinerant magnets R2Mo2O7 [10].…”

Section: Introductionsupporting

confidence: 80%

Double exchange model on triangular lattice: Non-coplanar spin configuration and phase transition near quarter filling

Zhang¹,

Zhang²,

Zhang³

et al. 2013

Physica B: Condensed Matter

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Unconventional anomalous Hall effect in frustrated pyrochlore oxides is originated from spin chirality of non-coplanar localized spins, which can also be induced by the competition between ferromagnetic (FM) double exchange interaction J H and antiferromagnetic superexchange interaction J AF . Here truncated polynomial expansion method and Monte Carlo simulation are adopted to investigate the above model on two-dimensional triangular lattice. We discuss the influence of the range of FM-type spin-spin correlation and strong electron-spin correlation on the truncation error of spin-spin correlation near quarter filling. Two peaks of the probability distribution of Email address: zhanggp96@ruc.edu.cn (G. P. Zhang) Preprint submitted to Physica B January 2, 2018 spin-spin correlation in non-coplanar spin configuration clearly show that non-coplanar spin configuration is an intermediate phase between FM and 120-degree spin phase. Near quarter filling, there is a phase transition from FM into non-coplanar and further into 120-degree spin phase when J AF continually increases. Finally the effect of temperature on magnetic structure is discussed.

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Section: Introductionsupporting

confidence: 80%

Double exchange model on triangular lattice: Non-coplanar spin configuration and phase transition near quarter filling

Zhang¹,

Zhang²,

Zhang³

et al. 2013

Physica B: Condensed Matter

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“…An alternative mechanism for robust, high temperature QAH states has generated much interest [16][17][18][19][20]. In certain correlated multi-orbital compounds, conduction electrons are coupled to localized magnetic moments (spins) at each lattice site.…”

Section: Introductionmentioning

confidence: 99%

Exotic magnetic orderings in the kagome Kondo-lattice model

et al. 2014

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We consider the Kondo-lattice model on the kagome lattice and study its weak-coupling instabilities at band filling fractions for which the Fermi surface has singularities. These singularites include Dirac points, quadratic Fermi points in contact with a flat band, and Van Hove saddle points. By combining a controlled analytical approach with large-scale numerical simulations, we demonstrate that the weak-coupling instabilities of the Kondo-lattice model lead to exotic magnetic orderings. In particular, some of these magnetic orderings produce a spontaneous quantum anomalous Hall state.

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“…TRsymmetry breaking via (magnetic) order requires rather specific and strong longer-range Coulomb interactions [16], because the Dirac cones' vanishing density of states at the Fermi level renders interaction-driven ordered states energetically less favorable. QAH states can more readily be induced in models with a finite density of states [17][18][19], especially in cases of quadratic band crossings [20], as for instance found in the checkerboard lattice, which exhibit a weak-coupling instability [20][21][22]. Another approach has been to consider spin-orbit coupled magnetic semi-conductors [23] or spinpolarized QSH states [12].…”

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confidence: 99%

Switchable Quantum Anomalous Hall State in a Strongly Frustrated Lattice Magnet

et al. 2012

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We establish that the interplay of itinerant fermions with localized magnetic moments on a checkerboard lattice leads to magnetic flux-phases. For weak itineracy the flux-phase is coplanar and the electronic dispersion takes the shape of graphene-like Dirac fermions. Stronger itineracy drives the formation of a non-coplanar, chiral flux-phase, in which the Dirac fermions acquire a topological mass that is proportional to a ferromagnetic spin polarization. Consequently the system self-organizes into a ferromagnetic Quantum Anomalous Hall state in which the direction of its dissipationless edge-currents can be switched by an applied magnetic field. PACS numbers: 71.27.+a , Introduction.-The study of topologically non-trivial states of matter is one of the hottest topics in present day condensed matter physics. An understanding of topological states requires a theoretical paradigm that goes far beyond the concept of global symmetry breaking that has originally been laid out by Landau. It is remarkable that the theoretical predictions on the existence of various topologically ordered states have rather swiftly led to the discovery of an entirely new class of materials, the topological insulators [1][2][3][4]. Recent pioneering experiments have confirmed the key signatures of nontrivial topology in certain materials, e.g. spin-momentumlocked undoubled Dirac fermions [5][6][7] and the Quantum Spin Hall (QSH) effect [8]. These topological insulators are timereversal (TR) invariant generalizations of the first, much older, topological state of matter, the famous Integer Quantum Hall states [9,10] that are induced by a magnetic field, which obviously breaks TR symmetry.In a seminal work in 1988, Haldane established that a magnetic field is not required to induce states with the same topology as IQH states [11]. It was shown that adding complex hopping to a graphene-like Hamiltonian for electrons on a honeycomb lattice opens up topologically nontrivial gaps at the Dirac points, which yields a topologically ordered, insulating state, referred to as a Quantum Anomalous Hall (QAH) state. An important feature of QAH states are edge channels, in which current can run only in one direction; in contrast to QSH states, on a single edge the opposite spin channel carrying the opposite current is absent [12]. QAH states would thus allow very robust, dissipationless charge transport along edge channels, as backscattering would be completely suppressed. However, while signatures of QAH behavior have been reported in some compounds [13][14][15], the QAH state is the only one among these topologically insulating states that remains to be unambiguously identified in experiment.The experimental difficulty is mirrored by the frailty of theoretical mass-generating mechanisms for a graphene-like kinetic energy with a linear dispersion at the Fermi level. TRsymmetry breaking via (magnetic) order requires rather specific and strong longer-range Coulomb interactions [16], because the Dirac cones' vanishing density of states at the Fermi level r...

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Frustration-Induced Insulating Chiral Spin State in Itinerant Triangular-Lattice Magnets

Cited by 67 publications

References 41 publications

Double exchange model on triangular lattice: Non-coplanar spin configuration and phase transition near quarter filling

Double exchange model on triangular lattice: Non-coplanar spin configuration and phase transition near quarter filling

Exotic magnetic orderings in the kagome Kondo-lattice model

Switchable Quantum Anomalous Hall State in a Strongly Frustrated Lattice Magnet

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