Skyrmion-induced bound states on the surface of three-dimensional topological insulators

Andrikopoulos, Dimitrios; Sorée, Bart; Boeck, J. De

doi:10.1063/1.4950759

Cited by 16 publications

(9 citation statements)

References 25 publications

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“…As another mechanism to manipulate magnetic textures on the surface of the topological insulator, utilizing a localized charge accumulation at textures has been theoretically proposed 17,19,41 . When the Fermi energy is located in the exchange gap, |E F | < |JM z |, the magnetic texture on the surface of the topological insulator accompanies an additional charge density due to the chiral edge states.…”

Section: Skyrmion Dynamicsmentioning

confidence: 99%

“…A topological insulator is a promising candidate, whose surface states have strong correlation between spin and currents known as spinmomentum locking 15,16 . Due to the spin-momentum locking, it is expected that more efficient magnetic manipulation can be achieved in the magnetic topological insulator, and electric manipulation of the magnetic texture [17][18][19] , spin-charge conversion 20,21 , and magnetization switching by spin-orbit torque [22][23][24] have been proposed and experimentally performed.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Skyrmion Dynamicsmentioning

confidence: 99%

Section: Introductionmentioning

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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“…Здесь мы рассматриваем только поверхностную область, где локализованы топологические поверхностные состояния, характеризующиеся дираковским конусом электронных состояний. Генерируемая спиновая текстура подобна текстуре магнитного вихревого скирмиона (vortex-skyrmion) [27,28] или мерона с вариацией спинового направления от перпендикулярного поверхности в центре к направлению параллельно поверхности на периферии [28]. При этом даже при температуре выше температуры дальнодействующего магнитного упорядочения спиновая ориентация параллельно поверхности на периферии генерируемого мерона жестко фиксируется соответствующим внутри-плоскостным направлением спинов топологических состояний.…”

Section: обсуждение результатовunclassified

“…В работах [27,28] анализировались эффекты индуцированного взаимодействия (proximity effect) дираковских поверхностных состояний ТИ с магнитными скирмионами, формируемыми в тонких металлических и диэлектических слоях на поверхности топологического изолятора. Было показано, что данное взаимодействие приводит к локализации дираковских состояний (electron confinement) и формированию связанных состояний на поверхности топологического изолятора, а также к появлению в гамильтониане для дираковских состояний " массового" или магнитного члена, открывающего щель в точке Ŵ. При этом вид данного " массового" члена и его влияние определяются магнитной текстурой скирмиона и эффективной спиновой поляризацией перпендикулярно поверхности, генерируемой скирмионом.…”

Section: обсуждение результатовunclassified

Механизм открытия щели в точке Дирака в электронном спектре Gd-допированного топологического изолятора

Шикин¹,

Естюнин²,

Королева³

et al. 2020

Физика Твердого Тела

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The electronic structure of magnetically-doped TI with stoichiometry Bi1.09Gd0.06Sb0.85Te3 in the region of the Dirac point has been studied in detail by angle-resolved photoelectron spectroscopy (ARPES) at various temperatures (above and below the Néel temperature, 1-35 K) and different polarizations of synchrotron radiation. It has shown that the energy gap in photoemission spectra opens at the Dirac point and remains open above the temperature of the long-range magnetic ordering, Tn. Measurements of magnetic properties by the superconducting magnetometry method (SQUID) have shown antiferromagnetic ordering with a transition temperature to the paramagnetic phase equal to 8.3 K. Study of the temperature dependence of the Dirac cone state intensity at the Г point by ARPES has confirmed the magnetic transition and has shown a possibility of its indication directly from photoemission spectra. A more detailed analysis of the splitting between the upper and lower Dirac cone states (i.e. the energy gap) at the Dirac point in the photoelectron spectra has shown the dependence of the measured gap on the synchrotron radiation polarization (about 28-30 meV for p-polarization and 22-25 meV for circularly polarized radiation of opposite chirality). The mechanism of opening the gap at a Dirac point above the Tn was proposed due to the “pairing” of the Dirac fermions with opposite momentum and spin orientation as a result of their interaction with the spin texture generated by photoemission in the region of the photoemission hole on a magnetic impurity atom (Gd). It was shown that the gap at the Dirac point, measured above Tn, is dynamic and is formed directly during photoemission process. At the same time, the origin of the gap remains magnetic (even when the long-range magnetic ordering is destroyed) and is associated with the properties of the magnetic topological insulator that determines a practically unchanged size of the gap above Tn. The dynamic origin of the generated gap is confirmed by the dependence of its magnitude on the polarization of synchrotron radiation.

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“…1 In particular, we can expect the existence of the fermionic modes confined by a magnetic skyrmion. These modes may represent the surface states of a three-dimensional topological insulator that become localized on the skyrmions [17,18]. More generally, the presence of localized fermions may affect the usual pattern of interaction between the solitons providing an additional exchange interaction.…”

Section: Introductionmentioning

confidence: 99%

Fermion exchange interaction between magnetic Skyrmions

Perapechka

Shnir

2019

Phys. Rev. D

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We propose a new mechanism of exchange interaction between the solitons related with the presence of localized fermions. Since the Atiyah-Patodi-Singer index theorem implies that such modes always exist for any topological soliton, their appearance may significantly alter the usual pattern of interaction. We elaborate this possibility considering, as a particular example, the chiral magnetic skyrmions coupled to spin-isospin fermions. It is shown that there are sequences of fermionic modes localized on the skyrmions. We investigate the additional effect of exchange interaction between the soltions with localized fermionic modes and demonstrate the existence of a stable system of magnetic skyrmions bounded by the strong attractive interaction mediated by the chargeless fermions.

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Skyrmion-induced bound states on the surface of three-dimensional topological insulators

Cited by 16 publications

References 25 publications

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

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

Механизм открытия щели в точке Дирака в электронном спектре Gd-допированного топологического изолятора

Fermion exchange interaction between magnetic Skyrmions

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