Excitonic Bose-Einstein condensation in Ta2NiSe5 above room temperature

K. Seki, Y. Wakisaka, T. Kaneko, T. Toriyama, T. Konishi, T. Sudayama, N. L. Saini, M. Arita, H. Namatame, M. Taniguchi, N. Katayama, M. Nohara, H. Takagi, T. Mizokawa, and Y. Ohta
Phys. Rev. B 90, 155116 – Published 13 October 2014

Abstract

We show that finite temperature variational cluster approximation (VCA) calculations on an extended Falicov-Kimball model can reproduce angle-resolved photoemission spectroscopy (ARPES) results on Ta2NiSe5 across a semiconductor-to-semiconductor structural phase transition at 325 K. We demonstrate that the characteristic temperature dependence of the flat-top valence band observed by ARPES is reproduced by the VCA calculation on the realistic model for an excitonic insulator only when the strong excitonic fluctuation is taken into account. The present calculations indicate that Ta2NiSe5 falls in the Bose-Einstein condensation regime of the excitonic insulator state.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Received 4 March 2014
  • Revised 24 September 2014

DOI:https://doi.org/10.1103/PhysRevB.90.155116

©2014 American Physical Society

Authors & Affiliations

K. Seki1, Y. Wakisaka2, T. Kaneko1, T. Toriyama1, T. Konishi3, T. Sudayama2, N. L. Saini4, M. Arita5, H. Namatame5, M. Taniguchi5,6, N. Katayama7, M. Nohara8, H. Takagi9, T. Mizokawa2, and Y. Ohta1

  • 1Department of Physics, Chiba University, Inage-ku, Chiba 263-8522, Japan
  • 2Department of Physics and Department of Complex Science and Engineering, University of Tokyo, Kashiwa, Chiba 277-8561, Japan
  • 3Department of Nanomaterial Science, Chiba University, Inage-ku, Chiba 263-8522, Japan
  • 4Department of Physics, Sapienza University of Rome, 00185 Rome, Italy
  • 5Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima 739-0046, Japan
  • 6Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
  • 7Department of Applied Physics, Nagoya University, Chikusa-ku, Nagoya 464-8601, Japan
  • 8Department of Physics, Okayama University, Tsushima-naka, Okayama 700-8530, Japan
  • 9Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 90, Iss. 15 — 15 October 2014

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×