Shubnikov-de Haas oscillations and Fermi surfaces in transition-metal pentatellurides ZrTe<sub>5</sub>and HfTe<sub>5</sub>

Izumi, Mitsuru; Nakayama, Tomonobu; Uchinokura, K.; Harada, Shigeki; Yoshizaki, Ryozo; Matsuura, Etsuyuki

doi:10.1088/0022-3719/20/24/011

Cited by 26 publications

(23 citation statements)

References 20 publications

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“…Figure 1 shows the resistance as a function of temperature for two samples S1 and S2, with thickness of 160 nm and 80 nm respectively. As temperature decreases, the resistance shows a broad peak at about 145 K, which is known as the "resistivity anomaly", consistent with earlier experiments 38,39,40 . We also noticed that a few recent work has reported the "resistivity anomaly", at a much lower temperatures around 100 K 10,42 .…”

Section: Introductionsupporting

confidence: 89%

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Transport evidence for the three-dimensional Dirac semimetal phase inZrTe5

et al. 2016

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Topological Dirac semimetal is a newly discovered class of materials which has attracted intense attentions. This material can be viewed as a three-dimensional (3D) analog of graphene and has linear energy dispersion in bulk, leading to a range of exotic transport properties. Here we report direct quantum transport evidence of the 3D Dirac semimetal phase of layered material ZrTe 5 by angular dependent magnetoresistance measurements under high magnetic fields up to 31 T. We observed very clear negative longitudinal magnetoresistance induced by chiral anomaly under the condition of the magnetic field aligned only along the current direction. Pronounced Shubnikov-de Hass (SdH) quantum oscillations in both longitudinal magnetoresistance and transverse Hall resistance were observed, revealing anisotropic light cyclotron masses and high mobility of the system. In particular, a nontrivial π-Berry phase in the SdH oscillations gives clear evidence for 3D Dirac semimetal phase. Furthermore, we observed clear Landau level splitting under high magnetic field, suggesting possible splitting of the Dirac point into Weyl points due to broken time reversal symmetry. Our results indicate that ZrTe 5 is an ideal platform to study 3D massless Dirac and Weyl fermions in a layered compound.

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Section: Introductionsupporting

confidence: 89%

“…Layered material ZrTe 5 has been known for decades due to its large thermoelectric power 36,37 , resistivity anomaly 38 and quantum oscillations 39,40 . Earlier experimental results exhibited an extremely small ellipsoidal Fermi surface 40 with small effective mass in the chain direction.…”

Section: Introductionmentioning

confidence: 99%

Transport evidence for the three-dimensional Dirac semimetal phase inZrTe5

et al. 2016

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“…The sheets of HfTe 5 stack along the b-axis. HfTe 5 has been previously studied for its resistivity anomaly [22,23], thermoelectric properties [24] and quantum oscillations [25,26]. Previous ab initio study has predicted that HfTe 5 and ZrTe 5 crystals are located near the phase boundary between weak and strong topological insulators [27].…”

Section: Engineering Zhejiang University Hangzhou 310027 Chinamentioning

confidence: 99%

Chiral anomaly and ultrahigh mobility in crystallineHfTe5

Wang

Liu

et al. 2016

Phys. Rev. B

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HfTe 5 is predicted to be a promising platform for studying topological phases. Here through an electrical transport study, we present the first observation of chiral anomaly and ultrahigh mobility in HfTe 5 crystals. Negative magneto-resistivity in HfTe 5 is observed when the external magnetic and electrical fields are parallel (B//E) and quickly disappears once B deviates from the direction of E. Quantitative fitting further confirms the chiral anomaly as the underlying physics. Moreover, by analyzing the conductivity tensors of longitudinal and Hall traces, ultrahigh mobility and ultralow carrier density are revealed in HfTe 5 , which paves the way for potential electronic applications. Chiral anomaly is a quantum anomaly phenomenon that breaks the chiral symmetry and leads to the non-conservation of chiral current [1,2]. This anomaly was proposed to be observed in lattice system in 1983 [3]. Recently, the study of Weyl fermions pushes forward the realization of chiral anomaly in crystals [4][5][6]. In Dirac/Weyl semimetals, the axial current is non-conserved due to the chiral anomaly, and further leads to charge pumping effect between the Weyl nodes with opposite chirality. This anomaly effect is suggested to give rise to negative magneto-resistivity when the magnetic and electrical fields are parallel (B//E) [4]. Related experimental evidences have been intensively pursued in various condensed matter systems Here we present the first electrical transport evidence for the chiral anomaly and the ultrahigh mobility in HfTe 5 crystals.

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“…On the other hand, its monolayer form is also claimed to be a candidate of quantum spin Hall insulator 12,13 , which is very rare among the natural compounds 14 . Shubnikov-de Haas oscillations 10,15,16 , Zeeman Splitting 17,18 , and fractional quantum Hall effect 19 were also observed in bulk ZrTe5.Meanwhile in recent years the 2D family has been expanded to a wide range of materials including narrow bandgap semiconductors (e.g. black phosphorus 20,21 ), wide bandgap semiconductors (e.g.…”

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confidence: 99%

Observation of Optical and Electrical In-Plane Anisotropy in High-Mobility Few-Layer ZrTe₅

Qiu

Charnas

et al. 2016

Nano Lett.

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Transition metal pentatelluride ZrTe5 is a versatile material in condensed-matter physics and has been intensively studied since the 1980's. The most fascinating feature of ZrTe5 is that it is a 3D Dirac semimetal which has linear energy dispersion in all three dimensions in momentum space. Structure-wise, ZrTe5 is a layered material held together by weak interlayer van der Waals force. The combination of its unique band structure and 2D atomic structure provides a fertile ground for more potential exotic physical phenomena in ZrTe5 related to 3D Dirac semimentals. However the physical properties of its few-layer form have yet to be thoroughly explored. Here we report strong optical and electrical in-plane anisotropy of mechanically exfoliated few-layer ZrTe5. Raman spectroscopy shows significant intensity change with sample orientations, and the behavior of angle-resolved phonon modes at the Γ point is explained by theoretical calculation. DC conductance measurement indicates a 50% of difference along different in-plane directions. The diminishing of resistivity anomaly in few-layer samples indicates the evolution of band structure with reduced thickness. Low-temperature Hall experiment sheds lights on more intrinsic anisotropic electrical transport, with hole mobility of 3,000 and 1,500 cm 2 /V· s along a-axis and c-axis respectively. Pronounced quantum oscillations in magnetoresistance are observed at low temperatures with highest electron mobility up to 44,000 cm 2 /V· s.Keywords: ZrTe5 Single crystal, 2D material, optical anisotropy, electrical anisotropy, quantum oscillations 3The discovery of graphene 1 began a new era of condensed-matter research because of its unique two-dimensional Dirac band structure, which hosts many profound physical phenomena such as the anomalous integer quantum Hall effect (IQHE) 2 . Since then great efforts have been made towards expanding the spectrum of topological materials and bringing many conceptual materials into reality. Transition metal pentatellurides such as ZrTe5 and HfTe5 have been widely studied in bulk form since early 1980's due to their anomalous resistivity peak and X-ray diffraction intensity peak at low temperature 3,4 , large thermoelectric power 5 , pressure-induced superconductivity 6,7 , absence of a structural phase transition corresponding to resistivity anomaly 8 , and chiral magnetic effect 9 . In recent years, ZrTe5 research has been revived because of its non-trivial topological properties. Some theoretical predictions and experimental results 10,11 indicate that it is a 3D Dirac semimetal, a mimic of graphene with linear energy dispersion in all three directions. On the other hand, its monolayer form is also claimed to be a candidate of quantum spin Hall insulator 12,13 , which is very rare among the natural compounds 14 . Shubnikov-de Haas oscillations 10,15,16 , Zeeman Splitting 17,18 , and fractional quantum Hall effect 19 were also observed in bulk ZrTe5.Meanwhile in recent years the 2D family has been expanded to a wide range of mat...

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Shubnikov-de Haas oscillations and Fermi surfaces in transition-metal pentatellurides ZrTe₅and HfTe₅

Cited by 26 publications

References 20 publications

Transport evidence for the three-dimensional Dirac semimetal phase inZrTe5

Transport evidence for the three-dimensional Dirac semimetal phase inZrTe5

Chiral anomaly and ultrahigh mobility in crystallineHfTe5

Observation of Optical and Electrical In-Plane Anisotropy in High-Mobility Few-Layer ZrTe₅

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Shubnikov-de Haas oscillations and Fermi surfaces in transition-metal pentatellurides ZrTe5and HfTe5

Cited by 26 publications

References 20 publications

Transport evidence for the three-dimensional Dirac semimetal phase inZrTe5

Transport evidence for the three-dimensional Dirac semimetal phase inZrTe5

Chiral anomaly and ultrahigh mobility in crystallineHfTe5

Observation of Optical and Electrical In-Plane Anisotropy in High-Mobility Few-Layer ZrTe5

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Shubnikov-de Haas oscillations and Fermi surfaces in transition-metal pentatellurides ZrTe₅and HfTe₅

Observation of Optical and Electrical In-Plane Anisotropy in High-Mobility Few-Layer ZrTe₅