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Distinguishing a Mott Insulator from a Trivial Insulator with Atomic Adsorbates

Jinwon Lee, Kyung-Hwan Jin, and Han Woong Yeom
Phys. Rev. Lett. 126, 196405 – Published 13 May 2021
Physics logo See synopsis: A Mott Meter
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Abstract

In an electronic system with various interactions intertwined, revealing the origin of its many-body ground state is challenging and a direct experimental way to verify the correlated nature of an insulator has been lacking. Here we demonstrate a way to unambiguously distinguish a paradigmatic correlated insulator, a Mott insulator, from a trivial band insulator based on their distinct chemical behavior for a surface adsorbate using 1TTaS2, which has been debated between a spin-frustrated Mott insulator or a spin-singlet trivial insulator. We start from the observation of different sizes of spectral gaps on different surface terminations and show that potassium adatoms on these two surface layers behave in totally different ways. This can be straightforwardly understood from distinct properties of Mott and band insulators due to the fundamental difference of the half- and full-filled orbitals involved, respectively. This work not only solves an outstanding problem in this particularly interesting material but also provides a simple touchstone to identify the correlated ground state of electrons experimentally.

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  • Received 13 November 2020
  • Revised 9 March 2021
  • Accepted 12 April 2021

DOI:https://doi.org/10.1103/PhysRevLett.126.196405

© 2021 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

synopsis

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A Mott Meter

Published 13 May 2021

A new experimental method based on adsorption can indicate whether a material is a Mott insulator or a common insulator.

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Authors & Affiliations

Jinwon Lee1,2, Kyung-Hwan Jin1, and Han Woong Yeom1,2,*

  • 1Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Republic of Korea
  • 2Department of Physics, Pohang University of Science and Technology, Pohang 37673, Republic of Korea

  • *yeom@postech.ac.kr

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Issue

Vol. 126, Iss. 19 — 14 May 2021

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