Scholarlink

<p>The 4H<sub>b</sub> polytype of TaS<sub>2</sub> is a natural heterostructure of H and T-type layers. Intriguing recent evidence points towards a possibly chiral superconducting ground state, unlike the superconductivity found in other polytypes where the T layers are absent, requiring understanding of the possible contributions of electrons from the T layers. Here we use micro-focused angle resolved photoemission spectroscopy to reveal that the T termination of the 4H<sub>b</sub> structure is metallic, but a subsurface T layer - seen below an H termination and thus more representative of the bulk case - is gapped. The results imply a complete charge transfer of 1 electron per 13 Ta from the T to adjacent H layers in the bulk, but an incomplete charge transfer at the T termination, yielding a metallic Fermi surface with a planar-chiral character. A similar metallic state is found in an anomalous region with likely T-H-H’ stacking at the surface. Our results exclude cluster Mott localisation in either the bulk or surface of 4H<sub>b</sub>-TaS<sub>2</sub> and point to a scenario of superconductivity arising from Josephson-like tunneling between the H layers.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Charge transfer empties the flat band in 4Hb-TaS2, except at the surface

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年1月19日

查看全文
  • Mihir Date,
  • Hyeonhu Bae,
  • Alex Louat,
  • Gabriele Domaine,
  • Niels B. M. Schröter,
  • Enrico Da Como,
  • Binghai Yan,
  • Matthew D. Watson

摘要

The 4Hb polytype of TaS2 is a natural heterostructure of H and T-type layers. Intriguing recent evidence points towards a possibly chiral superconducting ground state, unlike the superconductivity found in other polytypes where the T layers are absent, requiring understanding of the possible contributions of electrons from the T layers. Here we use micro-focused angle resolved photoemission spectroscopy to reveal that the T termination of the 4Hb structure is metallic, but a subsurface T layer - seen below an H termination and thus more representative of the bulk case - is gapped. The results imply a complete charge transfer of 1 electron per 13 Ta from the T to adjacent H layers in the bulk, but an incomplete charge transfer at the T termination, yielding a metallic Fermi surface with a planar-chiral character. A similar metallic state is found in an anomalous region with likely T-H-H’ stacking at the surface. Our results exclude cluster Mott localisation in either the bulk or surface of 4Hb-TaS2 and point to a scenario of superconductivity arising from Josephson-like tunneling between the H layers.