FitModel_IETS_SpinFlip

chemicha edited this page Feb 3, 2016 · 3 revisions

Inelastic Tunneling Spectroscopy (IETS) - magnetic spin-flips

This fit model targets measurement data recorded with scanning tunneling spectroscopy on magnetic adsorbates. To model the inelastic tunneling signal it calculates the current by a convolution of the tip and sample density of states.

The integral for the current is calculated as follows:

Parameters:

  • V_bias: sample bias voltage
  • rho: density of states
  • f: Fermi-Dirac occupation of the density of states

The transition matrix element in the tunnel integral is calculated by the crystal field Hamiltonian:

Parameters:

  • D: uniaxial anisotropy
  • E: in-plane anisotropy
  • S: spin operator

Additionally the Zeeman contribution for an external magnetic field is added to the Hamiltonian:

Parameters:

  • g: Lande factor
  • mu_B: Bohr's magneton
  • B: magnetic field
  • S: spin operator

The Hamiltonian is diagonalized to calculate the transition probabilities between the spin orientations for a specific spin state. The occupation of the different orientations follows Boltzman statistics.

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