Néel矢量控制$\mathcal{PT}$对称反铁磁体中的约瑟夫森二极管效应
Néel-Vector Control of the Josephson Diode Effect in $\mathcal{PT}$-symmetric Antiferromagnets
- Anhui Province Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences（中国科学院合肥物质科学研究院强磁场科学中心低能量子材料与器件安徽省重点实验室）
- Science Island Branch of Graduate School, University of Science and Technology of China（中国科学技术大学研究生院科学岛分院）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究通过微观建模和对称性分析，发现$\mathcal{PT}$对称反铁磁约瑟夫森结的二极管效应和$\varphi_{0}$态可由Néel矢量控制，并发展通道分辨散射理论揭示其机制，为无场可调约瑟夫森二极管提供新平台。
AI中文摘要：
超导与磁性的相互作用在约瑟夫森结中产生了丰富的现象。在本信中，我们研究了由常规$s$波超导体和基于CuMnAs建模的$\mathcal{PT}$对称共线反铁磁体构成的约瑟夫森结。通过微观建模和对称性分析，我们展示了这些结同时表现出约瑟夫森二极管效应和$\varphi_{0}$态。值得注意的是，这两种效应都受Néel矢量控制：将其旋转$90^{\circ}$会同时关闭这两种效应，而反转它则会切换二极管的极性。为了揭示微观机制，我们发展了一种通道分辨的散射理论，该理论能够准确捕捉反常相位，并建立了二极管效应的精确条件。通道电流-相位关系的相互作用产生了可观的二极管效率，其大小和方向均可通过交换场进行调节。此外，格林函数约化识别出单个重整化的$\mathcal{PT}$简并带作为输运载流子，并精确再现了完整的电流幅度。我们的工作确立了$\mathcal{PT}$对称反铁磁体作为无场、高度可调的约瑟夫森二极管和$\varphi_{0}$结的多功能平台。
英文摘要：
The interplay of superconductivity and magnetism gives rise to rich phenomena in Josephson junctions. In this Letter, we study Josephson junctions formed by conventional $s$-wave superconductors and a $\PT$-symmetric collinear antiferromagnet modeled on CuMnAs. Using microscopic modeling and symmetry analysis, we show that these junctions exhibit both the Josephson diode effect and $φ_{0}$-junction states. Remarkably, both effects are controlled by the Néel vector: rotating it by $90^{\circ}$ switches off both, while reversing it switches the diode polarity. To reveal the microscopic mechanism, we develop a channel-resolved scattering theory that accurately captures the anomalous phases and establishes the exact condition for the diode effect. The interplay of the channel current-phase relations yields a sizable diode efficiency, tunable by both the magnitude and direction of the exchange field. Furthermore, a Green-function reduction identifies a single renormalized $\PT$-degenerate band as the transport carrier and precisely reproduces the full current amplitudes. Our work establishes $\PT$-symmetric antiferromagnets as versatile platforms for field-free, highly tunable Josephson diodes and $φ_{0}$ junctions.
