Shift charge and spin photocurrents in Dirac surface states of topological insulator

Kim, Kun Woo; Morimoto, Takahiro; Nagaosa, Naoto

doi:10.1103/physrevb.95.035134

Cited by 70 publications

(52 citation statements)

References 65 publications

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“…Shift current is a rather ubiquitous phenomenon in noncentrosymmetric systems. Actually, shift current has been studied or discussed for GaAs 77 , SbSI 78 , and warped surface state of the three-dimensional TI 79 . Furthermore, the shift spin current can be also considered, which can have an application to spintronics 79 .…”

Section: Nonlinear/nonreciprocal Photonic Responsesmentioning

confidence: 99%

“…As exemplified by the p–n junction and the shift current, the nonlinear nonreciprocity is the key to realize the ac-to-dc conversion. On this basis, the dc spin current generation is also possible by the ac (photo) excitation on the surface state of TI 79 . In the magnetic system with broken time-reversal symmetry , an even more variety of the nonlinear and nonreciprocal current controls are possible, as described in this article for the nonlinear conduction for the Rashba system under a magnetic field, the semi-magnetic TI, and the chiral-lattice magnet.…”

Section: Nonlinear/nonreciprocal Photonic Responsesmentioning

confidence: 99%

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Nonreciprocal responses from non-centrosymmetric quantum materials

2018

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Directional transport and propagation of quantum particle and current, such as electron, photon, spin, and phonon, are known to occur in the materials system with broken inversion symmetry, as exemplified by the diode in semiconductor p–n junction and the natural optical activity in chiral materials. Such a nonreciprocal response in the quantum materials of noncentrosymmetry occurs ubiquitously when the time-reversal symmetry is further broken by applying a magnetic field or with spontaneous magnetization, such as the magnetochiral effect and the nonreciprocal magnon transport or spin current in chiral magnets. In the nonlinear regime responding to the square of current and electric field, even a more variety of nonreciprocal phenomena can show up, including the photocurrent of topological origin and the unidirectional magnetoresistance in polar/chiral semiconductors. Microscopically, these nonreciprocal responses in the quantum materials are frequently encoded by the quantum Berry phase, the toroidal moment, and the magnetoelectric monopole, thus cultivating the fertile ground of the functional topological materials. Here, we review the basic mechanisms and emergent phenomena and functions of the nonreciprocal responses in the noncentrosymmetric quantum materials.

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Section: Nonlinear/nonreciprocal Photonic Responsesmentioning

confidence: 99%

Section: Nonlinear/nonreciprocal Photonic Responsesmentioning

confidence: 99%

Nonreciprocal responses from non-centrosymmetric quantum materials

2018

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“…Note that the spin torques characterized by the coefficients χ f 2 and χ d 2 coincide with the conventional adiabatic and non-adiabatic spin-transfer torques, respectively 2,3 . The coefficients are shown in FIG.2 with typical parameters for Bi 2 Se 3 35,36 . Although the Hall effect-driven spin torques are dominant in both the field-like and the damping-like spin torques, the other terms including the conventional spin-transfer torques give certain contributions.…”

Section: Spin Torquesmentioning

confidence: 99%

Theory of current-driven dynamics of spin textures on the surface of a topological insulator

Kurebayashi

Nagaosa

2019

Phys. Rev. B

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Spin-transfer torque is one of the important physical quantities to understand for successful application of topological insulators to spintronics. In this paper, we present analytical expressions of the spin-transfer torques on a surface of a magnetic topological insulator by including the higher-order contributions of momentum, k 2 -term and the hexagonal warping. We obtain six different types of the spin-transfer torque including both the field-like and the damping-like torques; the four of them appear only when the higher-order momentum contributions are included. In addition, we discuss the dynamics of magnetic skyrmions driven by the spin-transfer torques on the surface of the topological insulator. Unlike the skyrmion dynamics in conventional metals, we find that the dynamics significantly depends on the internal structure of magnetic textures.

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“…7 The size of the charge shift can be determined exactly from the phase evolution of the adiabatic wavefunctions, namely, the difference in the Berry connections of the occupied and unoccupied bands. 8 Thus, a precise analysis of the electronic structure is necessary for microscopic investigation of the BPVE and for design of materials for high-performance solar energy devices.…”

Section: Introductionmentioning

confidence: 99%

Releasing the hidden shift current in the TTF-CA organic molecular solid via symmetry lowering

Kim

Shin

et al. 2020

npj Comput Mater

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Bulk photovoltaic effect, characterized by an excitation-driven unbiased spontaneous photocurrent, has attracted substantial attention mainly due to its potential for harvesting solar energy. Here, we investigate the photovoltaic characteristics of organic molecular solids and focus on the association between the photocurrent and the crystal symmetry in the exemplary case of tetrathiafulvalene-p-chloranil. We perform comprehensive first-principles calculations, including direct evaluations of the excitedstate current via real-time propagations of the time-dependent density functional theory. We find that the charge shifting in the low-temperature phase is mainly driven by the intrachain ferroelectricity, which gives rise to a photocurrent not only in the visiblelight range but also near the band-edge infrared region. The shift current that is locked in the symmetry of the high-temperature phase can be released by introducing a potential asymmetry. We suggest that organic molecular solids can be exploited via appropriate engineering to lower the symmetry, aiming at room-temperature photovoltaics.

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Shift charge and spin photocurrents in Dirac surface states of topological insulator

Cited by 70 publications

References 65 publications

Nonreciprocal responses from non-centrosymmetric quantum materials

Nonreciprocal responses from non-centrosymmetric quantum materials

Theory of current-driven dynamics of spin textures on the surface of a topological insulator

Releasing the hidden shift current in the TTF-CA organic molecular solid via symmetry lowering

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