Disorder-induced Anderson-like localization for bidimensional thermoelectrics optimization

Thermoelectric materials could play an important role in global sustainable energy. However, improving thermoelectric efficiency has proved difficult, largely due to the complex interdependence of electronic properties of solids. Early work by loffe has developed into the standard thermoelectric optimization paradigm of tuning the electronic carrier concentration in semiconductors. Although the localization theory of electrons by Anderson and Mott has developed in parallel, its potential for thermoelectrics optimization has not been explored. Here, we show that structural-disorder-induced electron localization also provides an effective optimization strategy for thermoelectric materials. By using a transport model that includes the relevant physics of localization, it is shown that the maximum thermoelectric figure of merit can be increased similar to 20% by tuning both carrier concentration and disorder. The benefit of slight disorder is confirmed in two model Ge-Sb-Te material systems. Particularly for highly degenerate semiconductors, this bidimensional optimization strategy provides a new methodology to attain high thermoelectric performance.