节状狄拉克费米子通过干净d波超导体的赝扩散传输

节线半金属的界面：鼓态、输运与折射

Interfaces of nodal-line semimetals: drum states, transport and refraction

该研究分析拓扑节线半金属界面与薄板结构，揭示边界条件对表面态、鼓态杂化及输运特征的影响，并发现弹道输运中的完美透射共振角与径向非均匀电流分布。

Prediction of $\mathrm{TiRhAs}$ as a Dirac Nodal Line Semimetal via First-Principles Calculations

Using first-principles calculations we predict that $\mathrm{TiRhAs}$, a previously synthesized compound, is a Dirac nodal line (DNL) semimetal. The DNL in this compound is found to be protected both by the combination of inversion and time-reversal symmetry, and by a reflection symmetry, in the absence of spin-orbit coupling (SOC). Our calculations show that band velocities associated with the nodal line have a high degree of directional anisotropy, with in-plane velocities $v_\perp$ perpendicular to the nodal line between $1.2-2.8\times10^5$ m/s. The crossings along the DNL are further found…

Disorder- and Topology-Enhanced Fully Spin-Polarized Currents in Nodal Chain Spin-Gapless Semimetals

Recently discovered high-quality nodal chain spin-gapless semimetals $M$F$_3$ ($M$ = Pd, Mn) feature an ultra-clean nodal chain in the spin up channel residing right at the Fermi level and displaying a large spin gap leading to a 100\% spin-polarization of transport properties. Here, we investigate both intrinsic and extrinsic contributions to anomalous and spin transport in this class of materials. The dominant intrinsic origin is found to originate entirely from the gapped nodal chains without the entanglement of any other trivial bands. The side-jump mechanism is predicted to be negligibly …

节结超导体脏表面零能平态的稳定性

Stability of flat zero-energy states at the dirty surface of a nodal superconductor

本文讨论了在保持时间反演对称性的节结超导体表面出现的高度简并零能态的稳定性。这种表面态的存在是定义在清洁极限中的限制布里渊区中的非平凡拓扑数的直接结果。然而，在实验中，在真实超导体的表面附近不可避免地会出现势无序，这可能会提升零能量下的高简并度。我们表明，在零能量状态的手征本征值定义的指数可以用来衡量在零能量的存在下，潜在的障碍的简并度。并讨论了指数与拓扑数之间的关系。

Prediction of three-fold fermions in a nearly-ideal Dirac semimetal BaAgAs

Materials with triply-degenerate nodal points in their low-energy electronic spectrum produce crystalline-symmetry-enforced three-fold fermions, which conceptually lie between the two-fold Weyl and four-fold Dirac fermions. Here we show how a silver-based Dirac semimetal BaAgAs realizes three-fold fermions through our first-principles calculations combined with a low-energy effective $\mathbf{k.p}$ model Hamiltonian analysis. BaAgAs is shown to harbor triply-degenerate nodal points, which lie on its $C_{3}$ rotation axis, and are protected by the $C_{6v}$($C_2\otimes C_{3v}$) point-group symme…

扭转节点超导体中的Josephson效应

Josephson effects in twisted nodal superconductors

本文研究了 $d$ 波超导体扭转界面的 Josephson 效应，发现临界电流随温度和扭转角呈现非单调变化，Cooper pair 共隧穿在接近 $45^\circ$ 时诱导拓扑 $d+id$ 相，并分析了无序与干涉效应对超导相变的影响。