Folded superstructure and degeneracy-enhanced band gap in the weak-coupling charge density wave system 2H−TaSe2
Using high-resolution angle-resolved photoemission spectroscopy (ARPES), we have mapped out the reconstructed electronic structure in the commensurate charge-density-wave (CDW) state of quasi-two-dimensional transition metal dichalcogenide 2H-TaSe2. The observation of the fine structure near Brillou...
| Main Authors: | , , , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
American Physical Society
2018
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| _version_ | 1797060232794341376 |
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| author | Li, YW Jiang, J Yang, HF Prabhakaran, D Liu, ZK Yang, LX Chen, YL |
| author_facet | Li, YW Jiang, J Yang, HF Prabhakaran, D Liu, ZK Yang, LX Chen, YL |
| author_sort | Li, YW |
| collection | OXFORD |
| description | Using high-resolution angle-resolved photoemission spectroscopy (ARPES), we have mapped out the reconstructed electronic structure in the commensurate charge-density-wave (CDW) state of quasi-two-dimensional transition metal dichalcogenide 2H-TaSe2. The observation of the fine structure near Brillouin zone (BZ) center supplements the picture of Fermi surface folding in the 3×3 CDW state. In addition to the anisotropic CDW band gaps that energetically stabilize the system at the Fermi level in the first-order lock-in transition, we found band reconstruction at high binding energy, which can be well explained by the hybridization between main bands (MBs) and folded bands (FBs). Furthermore, in contrast to the perfectly nested quasi-one-dimensional system, triple-nesting-vector-induced CDW FBs increase the degeneracy of the band crossing and thus further enlarge the magnitude of band gap at certain momentum-energy positions. The visualization and modeling of CDW gaps in momentum-energy space reconciles the long-lasting controversy on the gap magnitude and suggests a weak-coupling Peierls physics in this system. |
| first_indexed | 2024-03-06T20:14:27Z |
| format | Journal article |
| id | oxford-uuid:2babc935-d868-40be-97d1-be2d3129d6cb |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T20:14:27Z |
| publishDate | 2018 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | oxford-uuid:2babc935-d868-40be-97d1-be2d3129d6cb2022-03-26T12:32:22ZFolded superstructure and degeneracy-enhanced band gap in the weak-coupling charge density wave system 2H−TaSe2Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:2babc935-d868-40be-97d1-be2d3129d6cbEnglishSymplectic Elements at OxfordAmerican Physical Society2018Li, YWJiang, JYang, HFPrabhakaran, DLiu, ZKYang, LXChen, YLUsing high-resolution angle-resolved photoemission spectroscopy (ARPES), we have mapped out the reconstructed electronic structure in the commensurate charge-density-wave (CDW) state of quasi-two-dimensional transition metal dichalcogenide 2H-TaSe2. The observation of the fine structure near Brillouin zone (BZ) center supplements the picture of Fermi surface folding in the 3×3 CDW state. In addition to the anisotropic CDW band gaps that energetically stabilize the system at the Fermi level in the first-order lock-in transition, we found band reconstruction at high binding energy, which can be well explained by the hybridization between main bands (MBs) and folded bands (FBs). Furthermore, in contrast to the perfectly nested quasi-one-dimensional system, triple-nesting-vector-induced CDW FBs increase the degeneracy of the band crossing and thus further enlarge the magnitude of band gap at certain momentum-energy positions. The visualization and modeling of CDW gaps in momentum-energy space reconciles the long-lasting controversy on the gap magnitude and suggests a weak-coupling Peierls physics in this system. |
| spellingShingle | Li, YW Jiang, J Yang, HF Prabhakaran, D Liu, ZK Yang, LX Chen, YL Folded superstructure and degeneracy-enhanced band gap in the weak-coupling charge density wave system 2H−TaSe2 |
| title | Folded superstructure and degeneracy-enhanced band gap in the weak-coupling charge density wave system 2H−TaSe2 |
| title_full | Folded superstructure and degeneracy-enhanced band gap in the weak-coupling charge density wave system 2H−TaSe2 |
| title_fullStr | Folded superstructure and degeneracy-enhanced band gap in the weak-coupling charge density wave system 2H−TaSe2 |
| title_full_unstemmed | Folded superstructure and degeneracy-enhanced band gap in the weak-coupling charge density wave system 2H−TaSe2 |
| title_short | Folded superstructure and degeneracy-enhanced band gap in the weak-coupling charge density wave system 2H−TaSe2 |
| title_sort | folded superstructure and degeneracy enhanced band gap in the weak coupling charge density wave system 2h tase2 |
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