Direction of current with increase in electrode temperature

[physics]

Hello,

For a two probe heterostructure device, the direction of current change from positive to negative with increase in  left (or right) electrode temperature. What could be possible explanation?

Thank you

[Anders Blom]

This is complex to discuss without specifics. The heterogeneous case is much more complex since there is charge redistribution even at zero bias to align the Fermi levels. There is a close analogy with the p-n junction in classical electronics, perhaps that concept helps you analyze your system.