Research
ARPES Spectroscopy
Angularly Resolved Photoemission Spectroscopy (ARPES) is an experimental technique which measures a material's spectral function, resolved by momentum and by energy. It is a direct probe of the electronic spectrum. ComDMFT and ComRISB calculate the electronic spectrum, and their results can be compared to ARPES experimental results. For example, see our results on FeSb2, which has attracted interest because of its very large thermopower. For more examples, see this publication list.
Experimental ARPES spectra and theoretical spectra of FeSb2.(a) and (b) Full ARPES 3D mapping. (c)–(f) ARPES spectra at different high-symmetric directions in the BZ. (g)–(j) The spectra visualized using the curvature methods. The α band is still visible in (f) and (j) due to the ky broadening. (k)–(n) qsGW+DMFT calculated spectral functions at 50 K along the same high-symmetry directions as ARPES data. From "Correlated electronic structure of colossal thermopower FeSb2: An ARPES and ab initio study", Phys. Rev. Research, v. 2, p. 023190, 2020.
RIXS Spectroscopy
Where ARPES uses electrons to measure spectral functions, Resonant Inelastic X-ray Scattering (RIXS) uses high energy photons.
Read about Comscope's EDRIXS code for predicting the experimental results of RIXS experiments.
High Performance Computation
Comsuite's LQSGW code (implementing DFT, GW, and qsGW) can scale to a thousand processors, and its Gutzwiller code and its RIXS code also use parallel computers. However the most parallellizable by far is our CTQMC code, which calculates the DMFT solution to the correlated impurity problem. ComCTQMC can easily use four thousand GPU nodes, i.e. all of the Summit supercomputer.
