Inelastic tunneling spectroscopy in a d-wave superconductor

Abstract

We propose a mechanism to use inelastic tunneling spectrosopy scanning tunneling microscope (STM) to detect a single spin in a d-wave superconductor and in a pseudogap state, based on a direct exchange coupling J between the surface electrons and the local spin S in a magnetic field. This coupling will produce a kink in a dI/dV characteristic at Zeeman energy of the spin ω0. We find that for relevant values of parameters signal scales as dI2/dV2≃(JN0)2Θ(eV−ω0) and could be in the range of 10−2 of the bare density of states where N0 is the density of states for surface electrons. Scattering in superconductor with the coherence peak at gap maximum Δ leads also to strong features at Δ+ω0. This suggests a different technique for a detection of a local spin excitation with STM. We also consider a detection of a local vibrational mode as a simple extension of the spin case.

Source-reported materials — not catalogue approval

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