Real, technologically relevant materials are incredibly complicated. Their complexity usually leaves them out of the reach of analytical methods. Fortunately, computational methods and the computing power to realize them have advanced far enough to calculate observable macroscopic material properties. These include dielectric response, thermal and transport properties, and the electronic and phononic band structures that engender them. This makes reliable simulations absolutely essential in contemporary materials science, as more often than not, general theories only offer a partial explanation, and the whole of the scientific story lurks in the specific details of the material and its thermodynamic circumstances.
Numerical simulation of analytical models and collaboration with ab-initio computation specialty groups is inherent in our work. An ab-initio calculation makes no biased assumptions about the simulated system, using only chemical constants of the atomic species and crystal structure as input. In other words, the scientific hypothesis should have no bearing on how the simulation is performed. This makes the comparison to experiment and theoretical interpretations very powerful and can provide a detailed mechanistic picture to explain our experimental observations. Our routine collaborators are Leeor Kronik and Olle Hellman (WIS), Andrew Rapp (U.Penn), and David Egger (TUM).
While full first-principle simulations of crystals require specialized teams and equipment, invaluable physical insight may be gained by testing simplified systems. Therefore, we perform in-house calculations to test our theoretical ideas on toy models, such as 1D-potential "surfaces" or approximated spectra that reproduce non-trivial trends with temperature. Developing our own theoretical skills and capabilities advances our ability to conceptualize experimental results, as well as improves our communication with specialized theory groups.