# Prof. Stefan Kurth

## Staff Ikerbasque

- stefan [dot] kurth [at] ehu [dot] es
- Country
- Germany
- Phone
- +34 943 018597
- Fax
- +34 943 018390

### Research Information

- Research Overview
### Foundations of density functional theory

Density functional theory (DFT) has become the most widely used tool to study the electronic structure of atoms, molecules and solids. Instead of trying to solve the Schr\"odinger equation of interacting electrons directly, the problem is cast in a way such as to make it tractable in an approximate, but in many cases surprisingly accurate way. The success of DFT is largely due to the availability of increasingly accurate approximations to the so-called exchange-correlation energy functional. Standard approximations like the local density and generalized gradient approximations (LDA and GGA's) approximate the exchange-correlation energy as an explicit functional of the density. Going beyond these explicit density functionals, we are particularly interested in the class of explicitly orbital-dependent approximations to the exchange-correlation energy which are typically more flexible although they often come at a higher computational cost.

### Time-dependent quantum transport

In recent decades the size of electronic devices has been reduced to dimensions on the nanometer scale. In the emerging field of “Molecular Electronics” it is envisioned to use even single molecules as active electronic devices. In order to describe electron transport through such nanoscale devices theoretically, a fully quantum-mechanical treatment is required. Most treatments of quantum transport to date are concerned with the description of the steady-state regime. Here we focus on a somewhat different and arguably more natural approach to transport: we start from the system in its equilibrium configuration, then drive it out of equilibrium by an external field (bias) and follow its time evolution, possibly towards a steady state. This time-dependent approach allows not only to study the steady state (under application of a DC bias) but also to naturally describe truely time-dependent transport phenomena such as, e.g., transients, AC bias, pumping, etc. In order to take the electronic interactions into account, we use the framework of time-dependent density functional theory.

### Related Research Areas

### Latest publications

- Thermoelectric efficiency in multi-terminal quantum thermal machines with steady-state density functional theory
- Nahual Sobrino, Roberto D'Agosta, Stefan Kurth

(2023) - Level occupation switching with density functional theory
- Nahual Sobrino, David Jacob, Stefan Kurth

Physical Review B**106**, 195124 (2022)