Observation of Optical and Electrical In-plane Anisotropy in High-mobility Few-layer ZrTe5

Abstract

Transition metal pentatelluride ZrTe5 is a versatile material in condensed-matter physics and has been intensively studied since the 1980s. 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 gamma 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 cm2/Vs along a-axis and c-axis respectively. Pronounced quantum oscillations in magneto-resistance are observed at low temperatures with highest electron mobility up to 44,000 cm2/Vs.

References in corpus (5)

• Anisotropic behaviors of massless Dirac fermions in graphene under periodic potential
• Transport evidence for the three-dimensional Dirac semimetal phase in ZrTe5
• Experimental evidence of large-gap two-dimensional topological insulator on the surface of ZrTe5
• Superconductivity in HfTe5 Induced via Pressures
• Quantum Oscillations at Integer and Fractional Landau Level Indices in ZrTe5

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• Bipolar Conduction is the Origin of the Electronic Transition in Pentatellurides: Metallic vs. Semiconducting Behavior
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• Thickness-tuned transition of band topology in ZrTe5 nanosheets
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• Gate-tunable multiband transport in ZrTe5 thin devices
• Unusual magnetoresistance oscillations in preferentially oriented p-type polycrystalline ZrTe5
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• Veselago focusing of anisotropic massless Dirac fermions
• Revealing the band structure of ZrTe${}_5$ using Multicarrier Transport
• Signature of pressure-induced topological phase transition in ZrTe${}_5$
• Turning ZrTe5 into semiconductor through atomic intercalation
• Contact transparency in mechanically assembled 2D material devices
• Abrupt switching of the anomalous Hall effect by field-rotation in nonmagnetic ZrTe5
• Crystallographic Reconstruction Driven Modified Mechanical Properties in Anisotropic Rhenium Disulfides