Transition between strong and weak topological insulator in ZrTe5 and HfTe5

Fan, Zongjian; Liang, Qifeng; Chen, Y. B.; Yao, Shu‐Hua; Zhou, Jian

doi:10.1038/srep45667

Cited by 99 publications

(108 citation statements)

References 35 publications

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“…Hall effect data shows electron-like carriers at low temperature [16], implying some of these additional bands must be populated and Dirac-like or massive Dirac-like features should be present. Note that these features are extremely sensitive to cell volume and strain [17], which may explain the conflicting experimental reports on the electronic properties and topological signatures in ZrTe 5 [4][5][6][7][8][9][10][11][12][13][14].…”

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confidence: 97%

“…This anomaly is strongly sample dependent, ranging in its position from ∼ 10K to 150K. Recently, it has been suggested that the topological nature of the band structure and associated transport properties of ZrTe 5 depend strongly on the growth technique [17]. Nevertheless, the complicated history of this material highlights the need for robust low-energy signatures of Dirac-like band structures.…”

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confidence: 99%

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Thermodynamic signature of Dirac electrons across a possible topological transition in ZrTe5

et al. 2018

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We combine transport, magnetization, and torque magnetometry measurements to investigate the electronic structure of ZrTe5 and its evolution with temperature. At fields beyond the quantum limit, we observe a magnetization reversal from paramagnetic to diamagnetic response, which is characteristic of a Dirac semi-metal. We also observe a strong non-linearity in the magnetization that suggests the presence of additional low-lying carriers from other low-energy bands. Finally, we observe a striking sensitivity of the magnetic reversal to temperature that is not readily explained by simple band-structure models, but may be connected to a temperature dependent Lifshitz transition proposed to exist in this material.Thermodynamic signatures of the topological nature of a material have become increasingly important as numerous new topological insulator, Weyl, and Dirac materials are predicted [1][2][3]. In this study we focus on ZrTe 5 , a material whose topological nature is hotly debated; it has been predicted and verified as a Dirac semimetal [4][5][6][7][8], a topological insulator [9][10][11][12] and a trivial semiconductor [13,14]. In addition to its potential topological nature, there is also an unusual anomaly in the temperature dependence of the resistivity that has been conjectured to originate from a Lifshitz transition [15,16]. This anomaly is strongly sample dependent, ranging in its position from ∼ 10K to 150K. Recently, it has been suggested that the topological nature of the band structure and associated transport properties of ZrTe 5 depend strongly on the growth technique [17]. Nevertheless, the complicated history of this material highlights the need for robust low-energy signatures of Dirac-like band structures.We study the magnetic behavior of ZrTe 5 as it approaches and surpasses its quantum limit -the magnetic field at which all electrons are collapsed into the lowest, ν = 0 Landau level. In the most general case, all materials show some small degree of orbital diamagnetism arising from the local orbital moment of the ions. Trivial metals show an additional Landau diamagnetism arising from the orbital motion of their itinerant electrons. In a previous study of NbAs [18], we showed that topological metals exhibit a low-field paramagnetic response originating from their unique Landau quantization, which for a Dirac fermion in a magnetic field B along z is given bywhere ν is the Landau index, v F the Fermi velocity and γ is the quantum correction term which is 1/2 for trivial metals, but in Dirac systems γ = 0 due to the non-trivial Berry's phase. The Berry's phase associated with this quantization is often used as evidence for the existence of non-trivial topology, which can in principle be extracted from a plot of the Landau indices versus inverse magnetic field [19]. However, the influence of Zeeman splitting, the complicating effects of conductivity contributions from other bands and the presence of a Dirac mass can make this extraction unreliable, particularly in three dimensions [20,21]. Instea...

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Thermodynamic signature of Dirac electrons across a possible topological transition in ZrTe5

et al. 2018

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“…It has attracted substantial interest lately in the wave of Dirac and topological material exploration [2], due to the theoretical prediction of a large-gap quantum spin Hall insulator phase in its monolayer form [3]. Theory also predicts that the electronic structure of bulk ZrTe 5 resides near the phase boundary between weak and strong topological insulators (TIs) [3,4], providing an ideal platform for studying topological phase transitions. Surface-sensitive spectroscopy techniques such as angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling spectroscopy have recently been used to probe the surface and bulk states of ZrTe 5 [5][6][7][8][9][10][11].…”

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confidence: 99%

Landau-level spectroscopy of massive Dirac fermions in single-crystalline ZrTe5 thin flakes

et al. 2017

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We report infrared magneto-spectroscopy studies on thin crystals of an emerging Dirac material ZrTe5 near the intrinsic limit. The observed structure of the Landau level transitions and zero-field infrared absorption indicate a two-dimensional Dirac-like electronic structure, similar to that in graphene but with a small relativistic mass corresponding to a 9.4 meV energy gap. Measurements with circularly polarized light reveal a significant electron-hole asymmetry, which leads to splitting of the Landau level transitions at high magnetic fields. Our model, based on the Bernevig-Hughes-Zhang effective Hamiltonian, quantitatively explains all observed transitions, determining the values of the Fermi velocity, Dirac mass (or gap), electron-hole asymmetry, and electron and hole g-factors.

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“…This conclusion should also apply to other MX 2 /h-BN vdWHs. [76,77] The study of a vdWH of MX 2 based on other 2D insulators is of great interest and a new opportunity to improve the performance of TMD-based optoelectronic devices. [53] Copyright 2015, Macmillan Publishers Limited.…”

Section: Figurementioning

confidence: 99%

“…b) Band alignment of the MoS 2 /graphene vdWH at equilibrium state. [141,160] In addition, a WS 2 / Bi 2 Te 3 photodetector with wide photoresponse range from 370 to 1550 nm and short response time of ≈20 ms has been demonstrated by Fan et al [76] Its photoresponsivity and detectivity were measured up to 30.7 A W −1 and 2.3 × 10 11 cm Hz 1/2 W −1 , respectively. c) Band alignment and working mechanism of the MoS 2 /graphene vdWH.…”

Section: Photodetectorsmentioning

confidence: 99%

Recent Advances in van der Waals Heterojunctions Based on Semiconducting Transition Metal Dichalcogenides

Cheng

et al. 2018

Adv Elect Materials

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Due to the direct bandgap with coupled spin–valley physics, semiconducting MX2 (M = Mo, W; X = S, Se) materials have attracted considerable attention and have numerous proposed applications. With the development of 2D materials research, many 2D materials have been discovered, such as insulators, semiconductors, ferromagnetic semiconductors, topological insulators, metals, and ferromagnetic metals. van der Waals heterojunctions (vdWHs), based on MX2 and other 2D materials, have attracted increasing attention because of their various potential applications, such as field effect transistors, solar cells, photodetectors, light emitting diodes, and lasers. Based on the functionality of 2D materials, vdWHs are classified into six classes: MX2/semiconductors, MX2/insulators, MX2/topological insulators, MX2/ferromagnetic semiconductors, MX2/metals, and MX2/ferromagnetic metals. For each class of vdWHs, the structural, electronic, and optical properties, as well as potential applications in electronics and optoelectronics, are reviewed. Finally, an overview of perspectives and challenges regarding vdWHs based on MX2 materials is presented.

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Transition between strong and weak topological insulator in ZrTe5 and HfTe5

Cited by 99 publications

References 35 publications

Thermodynamic signature of Dirac electrons across a possible topological transition in ZrTe5

Thermodynamic signature of Dirac electrons across a possible topological transition in ZrTe5

Landau-level spectroscopy of massive Dirac fermions in single-crystalline ZrTe5 thin flakes

Recent Advances in van der Waals Heterojunctions Based on Semiconducting Transition Metal Dichalcogenides

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