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Title: Gap-like feature observed in the non-magnetic topological insulators

Abstract

Non-magnetic gap at the Dirac point of topological insulators remains an open question in the field. Here, we present angle-resolved photoemission spectroscopy experiments performed on Cr-doped Bi2Se3 and showed that the Dirac point is progressively buried by the bulk bands and a low spectral weight region in the vicinity of the Dirac point appears. These two mechanisms lead to spectral weight suppression region being mistakenly identified as an energy gap in earlier studies. We further calculated the band structure and found that the original Dirac point splits into two nodes due to the impurity resonant states and the energy separation between the nodes is the low density of state region which appears to be like an energy gap in potoemission experiments. Furthermore, we supported our arguments by presenting photoemission experiments carried out with on- and off- resonant photon energies. Our observation resolves the widely debated questions of apparent energy gap opening at the Dirac point without long range ferromagnetic order in topological insulators.

Authors:
ORCiD logo; ; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source II (NSLS-II)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES); University of Connecticut; USDOE Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1604317
Report Number(s):
BNL-213701-2020-JAAM
Journal ID: ISSN 0953-8984
Grant/Contract Number:  
SC0012704; 4626510
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Physics. Condensed Matter
Additional Journal Information:
Journal Volume: 32; Journal Issue: 14; Journal ID: ISSN 0953-8984
Publisher:
IOP Publishing
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; topological insulators; time reversal symmetry; ARPES

Citation Formats

Yilmaz, T., Pertsova, A., Hines, W., Vescovo, E., Kaznatcheev, K., Balatsky, A. V., and Sinkovic, B. Gap-like feature observed in the non-magnetic topological insulators. United States: N. p., 2020. Web. https://doi.org/10.1088/1361-648X/ab6349.
Yilmaz, T., Pertsova, A., Hines, W., Vescovo, E., Kaznatcheev, K., Balatsky, A. V., & Sinkovic, B. Gap-like feature observed in the non-magnetic topological insulators. United States. https://doi.org/10.1088/1361-648X/ab6349
Yilmaz, T., Pertsova, A., Hines, W., Vescovo, E., Kaznatcheev, K., Balatsky, A. V., and Sinkovic, B. Wed . "Gap-like feature observed in the non-magnetic topological insulators". United States. https://doi.org/10.1088/1361-648X/ab6349. https://www.osti.gov/servlets/purl/1604317.
@article{osti_1604317,
title = {Gap-like feature observed in the non-magnetic topological insulators},
author = {Yilmaz, T. and Pertsova, A. and Hines, W. and Vescovo, E. and Kaznatcheev, K. and Balatsky, A. V. and Sinkovic, B.},
abstractNote = {Non-magnetic gap at the Dirac point of topological insulators remains an open question in the field. Here, we present angle-resolved photoemission spectroscopy experiments performed on Cr-doped Bi2Se3 and showed that the Dirac point is progressively buried by the bulk bands and a low spectral weight region in the vicinity of the Dirac point appears. These two mechanisms lead to spectral weight suppression region being mistakenly identified as an energy gap in earlier studies. We further calculated the band structure and found that the original Dirac point splits into two nodes due to the impurity resonant states and the energy separation between the nodes is the low density of state region which appears to be like an energy gap in potoemission experiments. Furthermore, we supported our arguments by presenting photoemission experiments carried out with on- and off- resonant photon energies. Our observation resolves the widely debated questions of apparent energy gap opening at the Dirac point without long range ferromagnetic order in topological insulators.},
doi = {10.1088/1361-648X/ab6349},
journal = {Journal of Physics. Condensed Matter},
number = 14,
volume = 32,
place = {United States},
year = {2020},
month = {1}
}

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