# Electric resistence

What causes electric resistance for a material (in terms of molecular or atomic level)?
Also, it should be possible to derive the resistance of a material by it's atomic/molecular properties theoretically, right? (without using voltage and current).

## Answers and Replies

mgb_phys
Homework Helper
The strength of the attachment of the electrons to the atoms and at lower temperatures the strength of the atomic bonds.
At least for metals and semiconductors you can calculate the resistance.

ZapperZ
Staff Emeritus
What causes electric resistance for a material (in terms of molecular or atomic level)?
Also, it should be possible to derive the resistance of a material by it's atomic/molecular properties theoretically, right? (without using voltage and current).

In most material, at ordinary temperatures, it is due to the electron-phonon scattering. What this means is that the vibration of the lattice of the material collides with the movie electrons (or holes). This is why the resistivity increases as the temperature goes up. The higher the temperature, the more the lattice vibrates, the more frequent the electrons/charge carriers scatter.

Zz.

In most material, at ordinary temperatures, it is due to the electron-phonon scattering. What this means is that the vibration of the lattice of the material collides with the movie electrons (or holes). This is why the resistivity increases as the temperature goes up. The higher the temperature, the more the lattice vibrates, the more frequent the electrons/charge carriers scatter.

Zz.

Assuming it's the same lattice vibration you are talking in the FAQ section:

Is there a relation between the electrical and optical resistance for a given material? Does the electric resistance change if the material is placed under light?

Is there a way to experimentally see the lattice vibration on a computer screen?, or it is a mathematical model that could explain every phenomena.