Ionics versus electronics, and the general case of mixed conductor


  • In commemoration of Paul Drude (1863–1906)


The article emphasizes the importance of ion transport for solid state physics in view of the significance of ionic charge carriers for compositional changes and electrochemical applications, but also in view of their importance for defining the electronic charge carrier density. Special emphasis is given (i) to the mixed conductor as the general case which encompasses the pure electronic conductor and the pure ionic conductor as special cases, (ii) to the bridge between high temperature and room temperature situation and (iii) to the modern fields of interfacial ion transport and nano-ionics.