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Spectroscopic signatures of Quasi One-Dimensional Crystallization at Domain Walls in the Mott Insulator TaS<sub>2</sub>

ORAL

Abstract

A tunable Mott state is fortuitous as it is a model system to study emergent phenomena due to broken symmetries like superconductivity, novel magnetic order and charge order, as a Mott band is tuned across Fermi energy (EF). In this work, we use scanning tunneling microscopy at 4K to study the Mott insulator, TaS2. Charge density wave domain walls in TaS2 create band tuning such that part of the lower Hubbard band crosses the EF, creating a mobile pool of charge near the domain walls. STM spectroscopic maps show that these charges crystallize into unexpected 1D patterns. To distinguish the charge patterns from ordinary bound states, we carry out noise spectroscopy measurements and find that the 1D patterns show distinct telegraphic noise signatures indicative of a fragile condensed state. Combined with the large ratio of Coulomb to kinetic energies in this system, our data and calculations are consistent with the formation of a short-range, fragile charge order like an incipient Wigner crystal. The observation of crystallization in a strongly correlated regime makes TaS2 a promising system for exploiting the charge and spin order in quasi 1D systems.

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Presenters

  • Anuva Aishwarya

    University of Illinois at Urbana-Champaign

Authors

  • Anuva Aishwarya

    University of Illinois at Urbana-Champaign

  • Sean Howard

    Department of Physics, University of Illinois at Urbana-Champaign, University of Illinois at Urbana-Champaign, Department of Physics and Frederick Seitz Materials Research Laboratory, University of Illinois Urbana-Champaign

  • Bikash Padhi

    University of Illinois at Urbana-Champaign

  • Lihai Wang

    Pohang University of Science and Technology

  • Sang-Wook Cheong

    Rutgers University, R-CEM & Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA, Rutgers Center for Emergent Materials, Rutgers University, Department of Physics and Astronomy, Center for Emergent Materials, Rutgers University; Max Planck POSTECH/Korea Research Initiative, Pohang University of Science and Technol, Physics and Astronomy, Rutgers University, Rutgers University, Physics and Astronomy, and Laboratory for Pohang Emergent Materials and Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science, Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA, Rutgers University, Piscataway, Department of Physics and Astronomy, Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, Department of Physics, Rutgers University, Physics & Astronomy, Rutgers University, Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Rutgers University, New Brunswick, Physics, Rutgers University, Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA

  • Philip Phillips

    University of Illinois at Urbana-Champaign

  • Vidya Madhavan

    Physics, University of Illinois at Urbana-Champaign, University of Illinois at Urbana-Champaign, Department of Physics, University of Illinois at Urbana-Champaign, Department of Physics and Frederick Seitz Materials Research Laboratory, University of Illinois Urbana-Champaign