Skip to main content

MINI REVIEW article

Front. Electron. Mater
Sec. Superconducting Materials
Volume 5 - 2025 | doi: 10.3389/femat.2025.1456147
This article is part of the Research Topic Unveiling Strongly Correlated Materials with Resonant Inelastic X-ray Scattering View all 3 articles

Excitonic insulator candidate Ta2NiSe5 and related transition-metal compounds studied by resonant inelastic x-ray scattering

Provisionally accepted
  • 1 Waseda University, Tokyo, Japan
  • 2 Université de Fribourg, Fribourg, Fribourg, Switzerland

The final, formatted version of the article will be published soon.

    Resonant inelastic x-ray scattering (RIXS) can probe electron-hole excitations in excitonic insulators (EIs) which are realized by Coulomb attractive interaction between electrons and holes in semimetals or narrow gap semiconductors. In the present article, we review the exotic electronic state of an EI candidate Ta2NiSe5 which is probed by Ni 2p-3d RIXS as well as Ni 2p x-ray photoemission/absorption spectroscopy. The RIXS results on the exotic electronic state under the electron-hole and electron-lattice correlations suggest requirement of a new theoretical scheme which can describe itinerant electron-hole excitations and the localized charge-transfer excitations as well as the electron-lattice interaction.

    Keywords: Resonant inelastic X-ray scattering (RIXS), Excitonic insulator candidate, Transition-metal chalcogenides, negative charge-transfer energy, Electron-hole excitations

    Received: 28 Jun 2024; Accepted: 15 Jan 2025.

    Copyright: © 2025 Mizokawa and Monney. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Takashi Mizokawa, Waseda University, Tokyo, Japan

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.