Software Utilities

hc2d

Features and Description

The FFLO critical field is the upper critical field (magnetic field causing the breakdown of superconductivity) of a clean quasi two-dimensional superconductor, where the external magnetic field lies in the superconducting plane.

The difference between s- and d- wave superconductors lies in the order parameter (energy gap). The gap of an s-wave superconductor is the same for all wave-vectors k, while that of a d-wave superconductor has nodes and is thus a function of k. This results in similar, but different superconducting properties, including a slightly higher upper critical field for d-wave superconductors.

In a superconductor, two electrons with opposite spin pair up to build a so-called Cooper-pair. When an external field is switched on, there are two mechanisms that break up the Cooper-pair: paramagnetic and orbital pair-breaking.

Assuming that the external field lies in the superconducting plane, only paramagnetic pair-breaking takes effect in a 2d superconductor. Increasing the film thickness causes an increase in the orbital pair-breaking effect and reduces the upper critical field, which means that the field, at which superconductivity breaks down, gets smaller. The same happens when increasing the tilt-angle of the external field from parallel to perpendicular.

Download

Installation

• Unpack the tarball:

  tar -zxvf hc2d*.tar.gz

• Compile the program:

  make

• To run the program use:

  hc2d hc2d.cfg temperaturefile outputname

• Read the README.hc2d for details on how to use this program.

Documentation and Results

Feedback & Links

• hc2d on freshmeat: http://freshmeat.net/projects/hc2d/
• Please send all bugreports and feedback to: