Primary tunnel junction thermometry
  We describe the concept and experimental demonstration of primary thermometry based on a four probe measurement of a single tunnel junction embedded within four arrays of junctions. We show that in this configuration random sample specific and environment-related errors can be avoided. This method relates temperature directly to Boltzmann constant, which will form the basis of the definition of temperature and realization of official temperature scales in the future. 
Jukka P. Pekola, Tommy Holmqvist and Matthias Meschke