The Low-Energy, Local Density of States of an Isolated Vortex in an Extreme Type II Superconductor
✍ Scribed by D. Waxman
- Publisher
- Elsevier Science
- Year
- 1993
- Tongue
- English
- Weight
- 700 KB
- Volume
- 223
- Category
- Article
- ISSN
- 0003-4916
No coin nor oath required. For personal study only.
✦ Synopsis
The local density of states of low energy electronic excitations in a vortex is investigated. Starting from the Bogoliubov Hamiltonian, we make the approximation of replacing the quadratic momentum dependence of the free particle kinetic energy by a linear dependence. We then work with a linearized order parameter profile of the vortex (\Delta(r) ; \Delta(r) \approx A^{\prime}(0) r). where (r) is the distance from the vortex axis. The resulting theory has a simple operator structure and is exactly diagonalizable. It leads to a sequence of "oscillator-like" excitations in the core of the vortex. The low energy behaviour is contained in the zeroth oscillator level and when the excitation energy (E) and vortex profile obey (\Delta(r)^{2}-E^{2} \ll v_{\mathrm{F}} \Delta^{\prime}(0)), where (v_{\mathrm{F}}) is the Fermi velocity, we find that the leading behaviour in the local density of states is of the form (\left(\Delta(r)^{2}-E^{2}\right){ }^{1 / 2} \theta\left(\Delta(r)^{2}-E^{2}\right)) with (\theta(x)) a Heaviside step function. This "edge" behaviour is clearly discernible in numerical calculations of the local density of states. . 1993 Academic Press. Inc.