General Physics Colloquium - Per Hedegård: 'Molecular electronics - new forces'
Oplysninger om arrangementet
Fys. Aud. (1523-318)
General Physics Colloquium
'Molecular electronics - new forces'
Niels Bohr Instituttet
If the atoms in a metallic wire is set in motion, a wave of disturbance will propagate through the metal, but will eventually settle down and only thermal oscillations of the atoms will remain. This can be understood by considering the forces on the atoms. They are harmonic forces leading to characteristic oscillations, friction forces which takes energy out of the motion and random thermal forces, directly related to friction and temperature through a relation first understood by Einstein.
If instead an electrical current is moving through the wire, the situation changes drastically, and new and hitherto unexplored forces will emerge: non-conservative "wind" forces, Lorentz-like forces that do no work, and there even is a possibility that the friction coefficient will change sign, so that the motion of the atoms will grow in amplitude! Such effects are to be particularly pronounced if the current is led through single molecules attached to the metallic wires.
Coffee/tea and cake will be served at 3 PM.