Limit Cycle and Anomalous Capacitance in the Kondo Insulator<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>SmB</mml:mi><mml:mn>6</mml:mn></mml:msub></mml:math>

Kim, D. J.; Grant, Ted; Fisk, Z.

doi:10.1103/physrevlett.109.096601

Cited by 44 publications

(62 citation statements)

References 18 publications

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“…Recently, it is recognized that this hybridization of odd‐parity f‐electrons with even‐parity d‐electrons can result in the TKI phase in SmB 6 at low temperatures where the hybridization gap fully opens 10. The existence of metallic surface states has been verified in various transport studies of SmB 6, such as the capacitive self‐oscillation experiment,11 the point‐contact spectroscopy,12 the nonlocal and thickness independent transport measurement 13, 14. ARPES measurement also reveals the three surface Dirac cones located at the Γ and two X points, respectively 15.…”

Section: Introductionmentioning

confidence: 99%

Magnetoresistance Anomaly in Topological Kondo Insulator SmB₆ Nanowires with Strong Surface Magnetism

Gan

et al. 2018

Advanced Science

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Topological Kondo insulators (TKIs) are a new class of topological materials in which topological surface states dominate the transport properties at low temperatures. They are also an ideal platform for studying the interplay between strong electron correlations and topological order. Here, hysteretic magnetoresistance (MR) is observed in TKI SmB6 thin nanowires at temperatures up to 8 K, revealing the strong magnetism at the surface of SmB6. It is also found that such MR anomaly exhibits an intriguing finite size effect and only appears in nanowires with diameter smaller than 58 nm. These nontrivial phenomena are discussed in terms of the latest Kondo breakdown model, which incorporates the RKKY magnetic interaction mediated by surface states with the strong electron correlation in SmB6. It would provide new insight into the nature of TKI surface states. Additionally, a non‐monotonically temperature dependent positive magnetoresistance is observed at intermediate temperatures, suggesting the possible impurity‐band conduction in SmB6, other than the surface state transport at low temperatures and the bulk‐band transport at high temperatures.

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Section: Introductionmentioning

confidence: 99%

Magnetoresistance Anomaly in Topological Kondo Insulator SmB₆ Nanowires with Strong Surface Magnetism

Gan

et al. 2018

Advanced Science

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“…The most puzzling issue is the lack of divergence in the resistivity at low temperatures, which has always been attributed to in-gap states [13][14][15][16]. Recently, there have been theoretical and experimental demonstrations that such in-gap states might be topological surface states [17][18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Crossover of Magnetoresistance from Fourfold to Twofold Symmetry in SmB₆ Single Crystal, a Topological Kondo Insulator

Yue

Wang

et al. 2015

J. Phys. Soc. Jpn.

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Topological Kondo insulators have been attracting great attention from the condensed-matter physics community due to their fascinating topological and strongly correlated properties. Here, we report angledependent c-axis magnetoresistance (MR) oscillations in a Kondo insulator, SmB 6 single crystal, in a magnetic field of up to 13 T rotated in the ab-plane. Four-fold symmetric MR oscillations are first observed above 8 K, which result from the four-fold (C 4 ) degeneracy of the bulk Fermi surface of SmB 6 . With decreasing temperature down to 2.3 K, the C 4 symmetry of the MR oscillations gradually weakens and C 2 symmetry appears. This demonstrates a crossover from three-dimensional bulk states to two-dimensional surface states and implies the possible emergence of topological nematic states. Our experimental observations shed new light on the metallic surface states and nematic states in the Kondo insulator SmB 6 .

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“…Qm, 71.20.Eh, 72.20.Ht Samarium Hexaboride (SmB 6 ), a strongly correlated mixed valence compound [1,2], has garnered much attention recently due to the discovery of a low temperature conducting surface state [3][4][5][6][7][8]. It is proposed to form a strongly interacting version of a Topological Insulator [9][10][11][12][13], with a Kondo Gap in the bulk and a gapless states on the surface that seems to be protected by time-reversal symmetry [7].…”

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confidence: 99%

Direct observation of surface-state thermal oscillations in SmB6 oscillators

et al. 2018

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SmB6 is a mixed valence Kondo insulator that exhibits a sharp increase in resistance following an activated behavior that levels off and saturates below 4K. This behavior can be explained by the proposal of SmB6 representing a new state of matter, a Topological Kondo insulator, in which a Kondo gap is developed and topologically protected surface conduction dominates low temeprarture transport. Exploiting its non-linear dynamics, a tunable SmB6 oscillator device was recently demonstrated, where a small DC current generates large oscillating voltages at frequencies from a few Hz to hundreds of MHz. This behavior was explained by a theoretical model describing the thermal and electronic dynamics of coupled surface and bulk states. However, a crucial aspect of this model, the predicted temperature oscillation in the surface state, hasn't been experimentally observed to date. This is largely due to the technical difficulty of detecting an oscillating temperature of the very thin surface state. Here we report direct measurements of the time-dependent surface state temperature in SmB6 with a RuO2 micro-thermometer. Our results agree quantitatively with the theoretically simulated temperature waveform, and hence support the validity of the oscillator model, which will provide accurate theoretical guidance for developing future SmB6 oscillators at higher frequencies.PACS numbers: 72.15. Qm, 71.20.Eh, 72.20.Ht Samarium Hexaboride (SmB 6 ), a strongly correlated mixed valence compound [1,2], has garnered much attention recently due to the discovery of a low temperature conducting surface state [3][4][5][6][7][8]. It is proposed to form a strongly interacting version of a Topological Insulator [9][10][11][12][13], with a Kondo Gap in the bulk and a gapless states on the surface that seems to be protected by time-reversal symmetry [7]. The lack of impurity conduction in the bulk has allowed the realization of a radio frequency oscillator device [15] based on SmB 6 micro-crystals, where a small DC current drives the SmB 6 crystal into an oscillating state and generates large oscillating voltages. This behavior was explained by a theoretical model [15], which utilized a coupling between two conduction channels, namely, metallic surface conduction and thermally activated bulk conduction which result in significant differences in sample heating under an applied current. While this Letter will focus on the verification of this model in a proposed topological Kondo insulator, a general seiconducting sample with metallic channels with electrical and thermal coupling can be described equally well. The proposed model can be written as follows:(1)Here I S and I 0 are the surface and applied currents through the sample, respectively; C is the total capacitance representing the combined internal and external capacitance ; G = (R S + R B )/R B where R S is the surface resistance and R B = R Solving this simultaneous set of equations yields oscillatory solutions of both temperature and crystal voltage which has a constant phase shift ...

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Limit Cycle and Anomalous Capacitance in the Kondo InsulatorSmB6

Cited by 44 publications

References 18 publications

Magnetoresistance Anomaly in Topological Kondo Insulator SmB₆ Nanowires with Strong Surface Magnetism

Magnetoresistance Anomaly in Topological Kondo Insulator SmB₆ Nanowires with Strong Surface Magnetism

Crossover of Magnetoresistance from Fourfold to Twofold Symmetry in SmB₆ Single Crystal, a Topological Kondo Insulator

Direct observation of surface-state thermal oscillations in SmB6 oscillators

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Limit Cycle and Anomalous Capacitance in the Kondo InsulatorSmB6

Cited by 44 publications

References 18 publications

Magnetoresistance Anomaly in Topological Kondo Insulator SmB6 Nanowires with Strong Surface Magnetism

Magnetoresistance Anomaly in Topological Kondo Insulator SmB6 Nanowires with Strong Surface Magnetism

Crossover of Magnetoresistance from Fourfold to Twofold Symmetry in SmB6 Single Crystal, a Topological Kondo Insulator

Direct observation of surface-state thermal oscillations in SmB6 oscillators

Contact Info

Product

Resources

About

Magnetoresistance Anomaly in Topological Kondo Insulator SmB₆ Nanowires with Strong Surface Magnetism

Magnetoresistance Anomaly in Topological Kondo Insulator SmB₆ Nanowires with Strong Surface Magnetism

Crossover of Magnetoresistance from Fourfold to Twofold Symmetry in SmB₆ Single Crystal, a Topological Kondo Insulator