New Method Improves Accuracy of Band Gap Calculations in Semiconductors Using Coupled-Cluster Theory
Researchers have applied interacting-bath dynamical embedding theory (ibDET) to significantly reduce finite-size errors in EOM-CCSD band gap calculations for ten semiconductors and insulators. Periodic EOM-CCSD is a high-accuracy quantum chemistry method for predicting electronic band structures, but its steep computational cost has historically restricted calculations to coarse k-point grids, introducing large errors. The work demonstrates a practical path to thermodynamic-limit accuracy in solid-state electronic structure calculations at reduced computational expense.
A study posted to arXiv presents the use of interacting-bath dynamical embedding theory (ibDET) to overcome a key bottleneck in periodic equation-of-motion coupled-cluster theory with singles and doubles (EOM-CCSD): the finite-size errors arising from coarse Brillouin-zone sampling. By enabling k-point meshes as dense as 10×10×10—well beyond what canonical periodic EOM-CCSD can handle—the authors achieve stable extrapolations to the thermodynamic limit for a benchmark set of ten semiconductors and insulators. EOM-CCSD with ibDET attains a mean absolute error of 0.27 eV relative to experimental band gaps, outperforming the widely used G₀W₀@PBE method under identical numerical settings in the PySCF software package. The study also benchmarks G₀W₀@HF on equal footing, providing a systematic comparison across methods. As an additional test, EOM-CCSD correctly captures the Zn 3d-band binding energy in ZnO, though it overestimates the band gap for that material. The authors argue that ibDET, as a systematically improvable Green's function embedding framework, offers a practical and scalable route to high-accuracy many-body electronic structure calculations in periodic systems.
What's missing
The study benchmarks only ten semiconductors and insulators, so generalizability to metals, strongly correlated systems, or materials with more complex electronic structures remains untested. Computational cost comparisons (wall-clock times, memory requirements) between ibDET-assisted EOM-CCSD and standard G₀W₀ are not detailed, leaving the practical scalability advantage incompletely quantified.
What different sources said
- arXiv physicsCenter
Resolving Finite-Size Errors in EOM-CCSD Band Gaps of Solids with Interacting-Bath Dynamical Embedding Theory
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