Observation of Quantum Hall Effect and Charge Density Wave in CaCu­<sub>4</sub>As<sub>2</sub> single crystal

ORAL

Abstract

Quantum Hall effect (QHE) is usually observed in 2D systems due to the quantization of electron gas at sufficiently large applied magnetic fields. Whereas, in a 3D system, the charge carriers are free to move in all special directions which essentially prevents the quantization of Hall conductance.  In search of new materials, we have grown single crystals of CaCu4As2 which crystallizes in the rhombohedral structure with three septuple layers in one unit cell. From thermal, electrical transport and temperature dependent single crystal x-ray diffraction measurements, we observe a transition at 52 K attributed to the structural and/or charge density wave (CDW) transition. The Shubnikov-de Haas (SdH) oscillation reveals a unique frequency at 255 T, and the angular dependence of this frequency confirms the 2D nature of the charge carriers. The inverse Hall resistance vs 1/B plot exhibits clear steps like features. Our detailed analysis confirms that these steps are due to the QHE. Our experimental results indicate that the QHE may be originated from a large number of parallel conduction channels and CDW enhances the 2D nature of the charge carrier.  Thus, CaCu4As2 provides a new platform to understand the coexistence of both CDW and QHE in a 3D system.

*We acknowledge the support of Beamline P24 of PETRA-III at DESY, Hamburg, Germany. We also acknowledge the Department of Atomic Energy (DAE) of the Government of India for financial support.

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Presenters

  • SOUVIK SASMAL

    • Tata Institute of Fundamental Research, Mumbai
    • Tata Institute of Fundamental Research (

Authors

  • SOUVIK SASMAL

    • Tata Institute of Fundamental Research, Mumbai
    • Tata Institute of Fundamental Research (

  • VIKAS SAINI

    • Tata Institute of fundamental Research, Mumbai
    • Tata Institute of fundamental Research

  • Sitaram Ramakrishnan

    • Laboratory of Crystallography, University of Bayreuth, 95447 Bayreuth, Germany

  • Gourav Dwari

    • Tata Institute of Fundamental Research, Mumbai

  • Bishal B Maity

    • Tata Insitute of Fundamental Research, Mumbai

  • Jinke Bao

    • University of Bayreuth
    • Argonne National Laboratory

  • Rajib Mondal

    • Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
    • UGC-DAE Consortium for Scientific Research, Kolkata Centre, Bidhannagar, Kolkata

  • Vikram Tripathi

    • Tata Institute of Fundamental Research, Mumbai

  • Bahadur Singh

    • Tata Institute of Fundamental Research
    • Tata Institute for Fundamental Research
    • TIFR
    • Tata Institute of Fundamental Research, Mumbai
    • Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai, India

  • A Thamizhavel

    • Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
    • Tata Institute of Fundamental Research, Mumbai
    • Tata Institute of Fundamental Research