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Title: Spectroscopic signature of moment-dependent electron–phonon coupling in 2 H-TaS 2

Here, charge density wave (CDW) order is ubiquitous among low-dimensional electronic systems, as realized in layered materials such as various 1 T and 2 H polytypes of transition metal dichalcogenides (TMDs). In particular, 2 H-TaS 2, a prominent member of the vast family of TMDs, hosts a canonical CDW phase transition whose mechanism remains controversial even after decades of research. Using state-of-the-art angle resolved photoemission spectroscopy (ARPES) measurements, we report, for the first time, pronounced many-body renormalizations in 2 H-TaS 2. These renormalizations are manifested by the presence of multiple slope changes, known as “kinks”, in the electronic dispersions. The temperature independence of the kink energies and their close correspondence with the phonon frequencies of the system evidence that these renormalizations are caused by electron–phonon interactions. In addition, the electron–phonon coupling parameter is momentum-dependent, and the CDW vector is not compatible with any of the Fermi surface nesting vectors. Collectively, these observations establish that the origin of the CDW transition in 2 H-TaS 2 is not the same as that of the Peierls ordering transition, rather this transition is triggered by strong electron–phonon coupling including its momentum anisotropy. The commonality between the ARPES data on 2 H-TaS 2 and thosemore » on 2H-TaSe 2 and 2 H-NbSe 2 rationalize the above interpretation of the CDW transition being generic to incommensurate CDW orders in 2 H polytypes of TMDs.« less
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [4] ; ORCiD logo [1]
  1. Univ. of Virginia, Charlottesville, VA (United States)
  2. Northwestern Univ., Evanston, IL (United States)
  3. Argonne National Lab. (ANL), Argonne, IL (United States)
  4. Northwestern Univ., Evanston, IL (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Journal of Materials Chemistry C
Additional Journal Information:
Journal Volume: 5; Journal Issue: 43; Journal ID: ISSN 2050-7526
Publisher:
Royal Society of Chemistry
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE
OSTI Identifier:
1411025

Wijayaratne, Kapila, Zhao, Junjing, Malliakas, Christos, Chung, Duck Young, Kanatzidis, Mercouri G., and Chatterjee, Utpal. Spectroscopic signature of moment-dependent electron–phonon coupling in 2H-TaS2. United States: N. p., Web. doi:10.1039/c7tc02641b.
Wijayaratne, Kapila, Zhao, Junjing, Malliakas, Christos, Chung, Duck Young, Kanatzidis, Mercouri G., & Chatterjee, Utpal. Spectroscopic signature of moment-dependent electron–phonon coupling in 2H-TaS2. United States. doi:10.1039/c7tc02641b.
Wijayaratne, Kapila, Zhao, Junjing, Malliakas, Christos, Chung, Duck Young, Kanatzidis, Mercouri G., and Chatterjee, Utpal. 2017. "Spectroscopic signature of moment-dependent electron–phonon coupling in 2H-TaS2". United States. doi:10.1039/c7tc02641b. https://www.osti.gov/servlets/purl/1411025.
@article{osti_1411025,
title = {Spectroscopic signature of moment-dependent electron–phonon coupling in 2H-TaS2},
author = {Wijayaratne, Kapila and Zhao, Junjing and Malliakas, Christos and Chung, Duck Young and Kanatzidis, Mercouri G. and Chatterjee, Utpal},
abstractNote = {Here, charge density wave (CDW) order is ubiquitous among low-dimensional electronic systems, as realized in layered materials such as various 1T and 2H polytypes of transition metal dichalcogenides (TMDs). In particular, 2H-TaS2, a prominent member of the vast family of TMDs, hosts a canonical CDW phase transition whose mechanism remains controversial even after decades of research. Using state-of-the-art angle resolved photoemission spectroscopy (ARPES) measurements, we report, for the first time, pronounced many-body renormalizations in 2H-TaS2. These renormalizations are manifested by the presence of multiple slope changes, known as “kinks”, in the electronic dispersions. The temperature independence of the kink energies and their close correspondence with the phonon frequencies of the system evidence that these renormalizations are caused by electron–phonon interactions. In addition, the electron–phonon coupling parameter is momentum-dependent, and the CDW vector is not compatible with any of the Fermi surface nesting vectors. Collectively, these observations establish that the origin of the CDW transition in 2H-TaS2 is not the same as that of the Peierls ordering transition, rather this transition is triggered by strong electron–phonon coupling including its momentum anisotropy. The commonality between the ARPES data on 2H-TaS2 and those on 2H-TaSe2 and 2H-NbSe2 rationalize the above interpretation of the CDW transition being generic to incommensurate CDW orders in 2H polytypes of TMDs.},
doi = {10.1039/c7tc02641b},
journal = {Journal of Materials Chemistry C},
number = 43,
volume = 5,
place = {United States},
year = {2017},
month = {9}
}