Probing Spin-Excitaions above the Ground State of 1T-TaS<sub>2</sub>

ORAL

Abstract

Spin-spin interactions can lead to exotic ground states with emergent excitations in frustrated quantum magnets. Such a system is the transition metal dichalcogenide 1T-TaS2 .While the material is electrically insulating and exhibits no magnetic ordering down to milikelvin temperatures, the specific heat has a linear fermionic-type contribution that suggests a large band-width. We analyse the low temperature specific heat data and torque magnetometry measurements to isolate the contribution of the spin excitations to the magnetization from the large background response. The magnetic torque is strongly anisotropic and has a singular response at low magnetic fields which we attribute to a continuous disassociation of singlet pairs. This picture is also supported by the perfect collapse of the specific heat data at various temperatures and magnetic fields onto a universal curve predicted for singlets with a random distribution of antiferromagnetic coupling strengths. We interpret our data in the framework of a quantum spin liquid ground state having a large bandwidth with minority spins forming an array of singlet pairs with a continuum of coupling constants. Finally, despite the presumed large spinon Fermi surface we could not observe quantum oscillations of the magnetization.

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Presenters

  • Itai Silber

    • Tel Aviv University
    • Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University

Authors

  • Itai Silber

    • Tel Aviv University
    • Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University

  • Itamar Kimchi

    • University of Colorado, Boulder
    • Department of Physics, University of Colorado
    • Physics, University of Colorado

  • David E Graf

    • Florida State University
    • National High Magnetic Field Laboratory, Florida State University
    • Department of Physics, National High Magnetic Field Laboratory, Florida State University, Florida, USA
    • National High Magnetic Field Laboratory
    • National High Magnetic Field Lab, Florida State University
    • National High Magnetic Field Laboratory and Department of Physics, Florida State University
    • Florida State Univ
    • Natl High Magnetic Field Lab
    • National High Magnetic Field Lab, Tallahassee, FL 32310, USA
    • National High Magnetic Field Laboratory, 1800 E. Paul Dirac Drive, Tallahassee, FL 32310, USA
    • National High Magnetic Field Laboratory-Florida State University
    • National High Magnetic Field Laboratory, Tallahassee, FL
    • NHMFL, Florida State University
    • NHMFL

  • Amit Kanigel

    • Department of Physics, Technion-Israel Institute of Technology
    • Physics, Technion - Israel Institute of Technology
    • Technion - Israel Institute of Technology

  • Yoram Dagan

    • Tel Aviv University
    • Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University