弹道石墨烯约瑟夫森结中的倏逝模卡西米尔-约瑟夫森力与栅控共振
Evanescent-mode Casimir-Josephson force and gate-controlled resonances in ballistic graphene Josephson junctions
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中文总结 AI 辅助
本研究建立弹道石墨烯约瑟夫森结相位依赖平衡力学响应的微观散射理论，揭示了倏逝模力的特性、栅控振荡与两种转变机制，拓展了超导诱导力学力的研究体系。
中文摘要 AI 辅助
我们建立了一种微观散射理论，用于研究弹道超导体-石墨烯-超导体约瑟夫森结中依赖于相位的平衡力学响应。计算基于嵌入归一化松原行列式的能量依赖型狄拉克散射矩阵，因此所得的力修正包含了所述理想模型的完整博戈留波夫-德热纳谱。在电荷中性点，完整行列式趋近于一个与ΔW/L²成正比的闭合形式倏逝模结果，在零温短结极限下，相位差为π时达到2ln2 ΔW/(πL²)。栅极掺杂会产生传播通道和法布里-珀罗结构，导致依赖相位的力修正δF=F(ϕ)-F(0)出现大幅振荡和符号反转。我们区分了由|μ|/Δ调控的带间到带内安德列夫转变，以及由|μ|L/(ℏv_F)调控的倏逝到传播转变。从同一能量依赖散射矩阵得到的精确实能隙下极点被用于判定镜面/带间和镜面反射/带内特性；在混合区域中，这些标签不被视为可单独测量的热力学力。我们还量化了完整行列式结果与冻结散射短结近似之间的差异，但未将该差异等同于纯连续体力。由此得到的依赖栅压和相位的力学信号，为早期超导诱导力学力的设想提供了狄拉克材料方向的拓展。
英文摘要
We develop a microscopic scattering theory of the phase-dependent equilibrium mechanical response of a ballistic superconductor-graphene-superconductor Josephson junction. The calculation is based on an energy-dependent Dirac scattering matrix embedded in a normalized Matsubara determinant, so the reported force correction contains the complete Bogoliubov-de Gennes spectrum of the stated ideal model. At charge neutrality the full determinant approaches a closed-form evanescent-mode result proportional to $ΔW/L^2$, reaching $2\ln 2\,ΔW/(πL^2)$ at phase difference $π$ in the zero-temperature short-junction limit. Gate doping produces propagating channels and Fabry-Pérot structure, causing large oscillations and sign reversals of the phase-dependent force correction $δF=F(ϕ)-F(0)$. We distinguish the interband-to-intraband Andreev crossover, controlled by $|μ|/Δ$, from the evanescent-to-propagating crossover, controlled by $|μ|L/(\hbar v_F)$. Exact real-energy subgap poles obtained from the same energy-dependent scattering matrix are used to diagnose specular/interband and retro/intraband character; these labels are not treated as separately measurable thermodynamic forces in the mixed regime. We also quantify the difference between the complete determinant result and the frozen-scattering short-junction approximation without identifying that difference with a pure continuum force. The resulting gate- and phase-dependent mechanical signal provides a Dirac-material extension of earlier superconductivity-induced mechanical-force proposals.
发表机构
- Korea Institute for Advanced Study（韩国高等科学研究院）
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