March

Picture of the Month - March 2022

Resistivity calculation using MD-KKR approach

The ab initio calculation of the temperature dependent electrical resistivity of materials still represents a great challenge. Methods such as the lowest order variational approximation to the Boltzmann transport equation are widely used, while the Keldysch formalism has been employed in our workgroup. (https://doi.org/10.1103/PhysRevB.96.165121) However, both of these formalisms require a prior calculation of the electron-phonon interaction self-energy. To eliminate this need, the MD-KKR formalism has recently been devised. A MD simulation of the material in question (here: copper) is carried out to obtain screenshots of a material at a certain temperature. These screenshots are used as input structures for calculating the transmission with the KKR code. From the tranmission, temperature dependent resistivity and electron-phonon self-energies are easily obtainable.
Also $k_\parallel$ dependent transmissions are obtained in this way and are displayed for different temperatures. At 0 K this transmission is 1 if states exist at the Fermi energy for this $k_\parallel$ vector and 0 otherwise. With increasing temperature the transmission of these states decreases due to the electron-phonon scattering effects within the material.

This picture was submitted by Prof. Dr. Christian Heiliger.

Further insights into the research activities of the ZfM groups can be found in the Gallery.