论文标题
超导NB的各向异性涡流（110）
Anisotropic vortices on superconducting Nb(110)
论文作者
论文摘要
我们研究了外部磁场中II型超导NB（110）的电子性质。扫描隧道光谱显示出复杂的涡旋形状，从圆形通过咖啡豆形到椭圆形发展，当将能量从超导间隙的边缘降低到费米水平。这种各向异性可追溯到Caroli-de-de-Gennes-Matricon状态的局部密度，该状态表现出依赖方向的分裂。氧化NB（110）表面会触发从干净到肮脏极限的过渡，淬灭涡旋结合状态，并导致涡流的各向同性外观。密度功能理论表明，NB（110）费米表面在γ点附近是体育场形。使用这些费米轮廓的Bogoliubov-De-Gennes理论中的计算始终重现实验结果。
We investigate the electronic properties of type-II superconducting Nb(110) in an external magnetic field. Scanning tunneling spectroscopy reveals a complex vortex shape which develops from circular via coffee bean-shaped to elliptical when decreasing the energy from the edge of the superconducting gap to the Fermi level. This anisotropy is traced back to the local density of states of Caroli-de-Gennes-Matricon states which exhibits a direction-dependent splitting. Oxidizing the Nb(110) surface triggers the transition from the clean to the dirty limit, quenches the vortex bound states, and leads to an isotropic appearance of the vortices. Density functional theory shows that the Nb(110) Fermi surface is stadium-shaped near the Γpoint. Calculations within the Bogoliubov-de-Gennes theory using these Fermi contours consistently reproduce the experimental results.
