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Title: Orbital selectivity causing anisotropy and particle-hole asymmetry in the charge density wave gap of 2 H - TaS 2

Here, we report an in-depth angle-resolved photoemission spectroscopy study on 2H–TaS 2, a canonical incommensurate charge density wave (CDW) system. This study demonstrates that just as in related incommensurate CDW systems, 2H–TaSe 2 and 2H–NbSe 2, the energy gap (Δ CDW) of 2H–TaS 2 is localized along the K-centered Fermi surface barrels and is particle-hole asymmetric. The persistence of Δ CDW even at temperatures higher than the CDW transition temperature T CDW in 2H–TaS 2, reflects the similar pseudogap behavior observed previously in 2H–TaSe 2 and 2H–NbSe 2. However, in sharp contrast to 2H–NbSe 2, where ΔCDW is nonzero only in the vicinity of a few “hot spots” on the inner K-centered Fermi surface barrels, Δ CDW in 2H–TaS 2 is nonzero along the entirety of both K-centered Fermi surface barrels. Based on a tight-binding model, we attribute this dichotomy in the momentum dependence and the Fermi surface specificity of Δ CDW between otherwise similar CDW compounds to the different orbital orientations of their electronic states that participate in the CDW pairing. Our results suggest that the orbital selectivity plays a critical role in the description of incommensurate CDW materials.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [1] ;  [4] ;  [5] ;  [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)
  5. Univ. of Amsterdam, Amsterdam (The Netherlands)
Publication Date:
Grant/Contract Number:
AC02-06CH11357; FG02-01ER45927
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 96; Journal Issue: 12; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1411153
Alternate Identifier(s):
OSTI ID: 1378416