Photoinduced collective mode, inhomogeneity, and melting in a charge-order system

Seo, Hitoshi; Tanaka, Yasuhiro; Ishihara, Sumio

doi:10.1103/physrevb.98.235150

Cited by 11 publications

(7 citation statements)

References 32 publications

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“…In the MF theory, the manybody wave function is expressed as a direct product of onebody states, whose time-evolution is described by the MF Hamiltonian. Determining the MFs at each time from the many-body wave function, we compute the time-evolution of the one-body states with the extended Euler method [50][51][52][53][54][55]. The time-dependent magnetic field is explicitly given as,…”

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confidence: 99%

Majorana-Mediated Spin Transport in Kitaev Quantum Spin Liquids

et al. 2020

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We study the spin transport through the quantum spin liquid (QSL) by investigating the real-time and realspace dynamics of the Kitaev spin system with a zigzag structure in terms of the time-dependent Majorana mean-field theory. After the magnetic field pulse is introduced to one of the edges, the spin moments are excited in the opposite edge region although no spin moments are induced in the Kitaev QSL region. This unusual spin transport originates from the fact that the S = 1/2 spins are fractionalized into the itinerant and localized Majorana fermions in the Kitaev system. Although both Majorana fermions are excited by the magnetic pulse, only the itinerant Majorana fermions flow through the bulk regime without the spin excitation, resulting in the spin transport in the Kitaev system. We also demonstrate that this phenomenon can be observed even in the system with the Heisenberg interactions using the exact diagonalization.

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confidence: 99%

Majorana-Mediated Spin Transport in Kitaev Quantum Spin Liquids

et al. 2020

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“…By solving the mean-field Hamiltonian self-consistently, we obtain the initial mean-field parameters and wave function. After that, we evaluate the time-evolution of the ground state using extended Euler methods [34][35][36][37][38][39].…”

Section: Model and Methodsmentioning

confidence: 99%

Section: Appendix A: Implementation Of Majorana Mean-field Theorymentioning

confidence: 99%

Role of Majorana fermions in spin transport of anisotropic Kitaev model

Taguchi,

Murakami,

Koga

et al. 2021

Preprint

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We study a quantum spin Kitaev model with zigzag edges to clarify the effects of anisotropy in the exchange couplings on the spin propagation. We simulate the spin and Majorana dynamics triggered by a magnetic pulse, using the real-space time-dependent Majorana mean-field theory. When the anisotropy is small, the dispersion of the itinerant Majorana fermions remains gapless, where the velocity of the spin propagation matches the group velocity of the itinerant Majorana fermions at the nodal points. On the other hand, in the gapped system with a large anisotropy, the spin propagation is strongly suppressed although its nature depends on the shape of the pulse. The spin transport in the junction system described by the Kitaev models with distinct anisotropies is also addressed.

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“…We extend the Majorana MF theory for the time-dependent Hamiltonian in Eq. (3), following the conventional timedependent MF theory applied to correlated electron systems [73][74][75][76][77][78]. In this framework, each one-particle state |φ kν (t) evolves with time t obeying the Shrödinger equation:…”

Section: Methods a Time-dependent Majorana Mf Theorymentioning

confidence: 99%

Nonequilibrium Majorana dynamics by quenching a magnetic field in Kitaev spin liquids

Nasu

Motome

2019

Phys. Rev. Research

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The honeycomb Kitaev spin model provides a quantum spin liquid in the ground state, where the spin excitations are fractionalized into itinerant and localized Majorana fermions; the former spectrum has a broad continuum ranging up to a high energy, while the latter has a sharp peak at a low energy. Despite tremendous efforts, it remains elusive to clearly identify these distinct Majorana excitations in experiments. Here we show their manifestation in the time evolution after quenching the magnetic field, by using the time-dependent Majorana mean-field theory for both the ferromagnetic and antiferromagnetic Kitaev models. We find that the transient spin dynamics from the quantum spin liquid states is qualitatively different from the conventional spin precessions by the quench from the high-field forced-ferromagnetic state. We obtain peculiar time evolutions with distinct time scales, i.e., short-time decay of high-energy components associated with the itinerant Majorana excitations, and long-lived excitations at a low energy by the localized ones. These peculiar behaviors are caused by the energy transfer between the two Majorana quasiparticles after the field quench. Moreover, we find that the Majorana semimetal with the point nodes in equilibrium turns into a Majorana metal with the transient "Fermi surfaces" by the energy transfer. In particular, for the quench from the intermediate-field quantum spin liquid in the antiferromagnetic Kitaev model, the Fermi surfaces change their topology in the time evolution, which is regarded as a dynamical version of the Majorana "Lifshitz transition". Our results unveil that the realtime dynamics provides another route to not only the identification of the fractional Majorana excitations in candidate materials of Kitaev magnets but also unprecedented quantum phases that cannot be stabilized as the equilibrium states.

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Photoinduced collective mode, inhomogeneity, and melting in a charge-order system

Cited by 11 publications

References 32 publications

Majorana-Mediated Spin Transport in Kitaev Quantum Spin Liquids

Majorana-Mediated Spin Transport in Kitaev Quantum Spin Liquids

Role of Majorana fermions in spin transport of anisotropic Kitaev model

Nonequilibrium Majorana dynamics by quenching a magnetic field in Kitaev spin liquids

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