Scholarlink

<p>Superconductivity is observed in rhombohedral trilayer graphene in a narrow regime between the flavour-symmetric state and the symmetry breaking phase, which cannot be described by the conventional Bardeen-Cooper-Schrieffer theory. The measured coherence length, for instance, is roughly two orders of magnitude shorter than the value predicted by the Bardeen-Cooper-Schrieffer relation based on the large fermi velocity and an extremely low charge carrier density of the flavour-symmetric phase. To resolve the discrepancies, we propose that the rhombohedral trilayer graphene superconducting phase arises from the pairing of quasiparticles of the adjacent inter-valley coherent state. We illustrate the superconducting phenomenology using gapped Dirac cones with the chemical potential <i>μ</i> close to the valence band’s edge. Our findings indicate that the transition temperature <i>T</i><sub><i>c</i></sub> obeys <InlineEquation ID="IEq1"><EquationSource Format="TEX">\({T}_{c}\propto {\epsilon }_{D}\exp (-2/{\rho }_{\rm{qp}}U)\)</EquationSource><EquationSource Format="MATHML"><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>∝</mo><msub><mrow><mi>ϵ</mi></mrow><mrow><mi>D</mi></mrow></msub><mi>exp</mi><mrow><mo>(</mo><mrow><mo>−</mo><mn>2</mn><mo>/</mo><msub><mrow><mi>ρ</mi></mrow><mrow><mi mathvariant="normal">qp</mi></mrow></msub><mi>U</mi></mrow><mo>)</mo></mrow></math></EquationSource></InlineEquation> with the density of states <i>ρ</i><sub>qp</sub> of intervalley coherent state quasiparticles, which is much suppressed compared to predictions from the Bardeen-Cooper-Schrieffer theory. The coherence length <i>ξ</i> we predict behaves according to <InlineEquation ID="IEq2"><EquationSource Format="TEX">\(\xi \sim v/\sqrt{\mu {T}_{c}}\)</EquationSource><EquationSource Format="MATHML"><math><mi>ξ</mi><mo>~</mo><mi>v</mi><mo>/</mo><msqrt><mrow><mi>μ</mi><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></msqrt></math></EquationSource></InlineEquation> with <i>v</i> being the velocity of Dirac cone. Applying our assumption to a microscopic model, our predictions align well with experimental data and effectively capture key measurable quantities such as the transition temperature <i>T</i><sub><i>c</i></sub> and the coherence length <i>ξ</i> `without parameter fine-tuning.</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

Superconductivity from quasiparticle pairing of intervalley coherent state in rhombohedral trilayer graphene

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年5月28日

查看全文
  • Chun Wang Chau,
  • Shuai A. Chen,
  • K. T. Law

摘要

Superconductivity is observed in rhombohedral trilayer graphene in a narrow regime between the flavour-symmetric state and the symmetry breaking phase, which cannot be described by the conventional Bardeen-Cooper-Schrieffer theory. The measured coherence length, for instance, is roughly two orders of magnitude shorter than the value predicted by the Bardeen-Cooper-Schrieffer relation based on the large fermi velocity and an extremely low charge carrier density of the flavour-symmetric phase. To resolve the discrepancies, we propose that the rhombohedral trilayer graphene superconducting phase arises from the pairing of quasiparticles of the adjacent inter-valley coherent state. We illustrate the superconducting phenomenology using gapped Dirac cones with the chemical potential μ close to the valence band’s edge. Our findings indicate that the transition temperature Tc obeys \({T}_{c}\propto {\epsilon }_{D}\exp (-2/{\rho }_{\rm{qp}}U)\)Tc∝ϵDexp(−2/ρqpU) with the density of states ρqp of intervalley coherent state quasiparticles, which is much suppressed compared to predictions from the Bardeen-Cooper-Schrieffer theory. The coherence length ξ we predict behaves according to \(\xi \sim v/\sqrt{\mu {T}_{c}}\)ξ~v/μTc with v being the velocity of Dirac cone. Applying our assumption to a microscopic model, our predictions align well with experimental data and effectively capture key measurable quantities such as the transition temperature Tc and the coherence length ξ `without parameter fine-tuning.