Quantum chemical property calculations in the 10K to 1M atom range are now feasible. Over the last few months, several preprints have been posted to the arXiv. Traditional solid state theory assumes periodic boundary conditions, which is equivalent to assuming a structure of infinite extent. Quantum chemical techniques, by contrast, have always assumed a finite collection of atoms. And until recent times, “finite” meant on the order of 10-100 atoms!

With advances in algorithmics and in massively parallel computing, it became feasible in 2010 to compute at least some properties of material systems containing on the order of one million atoms [1]. Given that nano-scale electronic devices (for example, nano-dots and short transistor gates) can be well modelled with < 1M atoms, this is a timely development. Another approach, not yet to the 1M atom scale, is given in [2].

I include two papers addressing device transport properties [1,3]. The second is not as sophisticated as the first, but has the advantage of being more accessible.

To quote Richard Hamming, “The purpose of computing is insight, not numbers.” So it is in large-scale theoretical calculations. How do we know that all the (millions of) numbers coming out have any resemblance to reality? Papers [4,5] present a methodical looks at various of the theoretical techniques with the objective of answering how reliable we might find these methods to be in practical application.

Paper [6] considers theoretical methods to design energy storage and photoemissive materials.

Finally, paper [7] picks up the theme of inverse design. Given some desired properties, how can one design a material displaying those properties? In an abstract sense, inverse design is a generalization of the designer potentials approach to self-assembly that I reported on some time ago.

References:

[1] Lee et al., “Million Atom Electronic Structure and Device Calculations on Peta-Scale Computers”, arXiv:1003.4570

[2] Mohr et al., “Daubechies Wavelets for Linear Scaling Density Functional Theory”, arXiv:1401.7441

[3] Gross et al, “Kwant: a software package for quantum transport”, arXiv:1309.2926

[4] Keller and Reiher, “Determining Factors for the Accuracy of DMRG in Chemistry”, arXiv:1401.5497

[5] Shullenberger and Mattsson, “Quantum Monte Carlo applied to solids”, arXiv:1310.1047

[6] Nemeth, “Materials Design by Quantum-Chemical and other Theoretical/Computational Means: Applications to Energy Storage and Photoemissive Materials”, arXiv:1312.0699

[7] Weymuth and Reiher, “Inverse Quantum Chemistry: Concepts and Strategies for Rational Compound Design”, arXiv:1401.1512