Spring 2021

Ken Jordan served as a guest editor for a special issue of the Journal of Chemical Physics titled “Frontiers of stochastic electronic structure calculations.” Read part of the abstract below.

Abstract:
In recent years there has been a rapid growth in the development and application of new stochastic methods in electronic structure. These methods are quite diverse, from many-body wave function techniques in real space or determinant space to being used to sum perturbative expansions. This growth has been spurred by the more favorable scaling with the number of electrons and often better parallelization over large numbers of central processing unit (CPU) cores or graphical processing units (GPUs) than for high-end non-stochastic wave function based methods. This special issue of the Journal of Chemical Physics includes 33 papers that describe recent developments and applications in this area. As seen from the articles in the issue, stochastic electronic structure methods are applicable to both molecules and solids and can accurately describe systems with strong electron correlation.

The special issue tackles six subtopics: auxiliary-field quantum monte carlo, real-space methods, perturbation theory, quantum chemistry methods, application to finite systems, and application to infinite systems. Read more here.

Wei Xiong and Maysam Chamanzar were both recently awarded NSF CAREER grants for their outstanding work. 

Wei Xiong’s project will study the tradeoff between strength and ductility of alloy components created by additive manufacturing. His team aims to find a way to overcome the problem that the stronger a material is, the less ductile it becomes, and they will design new alloys that can be additively manufactured. This could help reduce the number of alloy powders needed for 3D printing, save the cost of alloy powder production for various engineering purposes, and provide recipes to recycle and reuse existing metal powders. 

Maysam Chamanzar’s research will present a new type of neural probe that uses graphene to change brain signals to electromagnetic waves. This will increase the number of recording channels without increasing the size of the probe since a large probe could cause brain damage. The research could provide insight into treatments for brain disorders like epilepsy, Parkinson’s and Alzheimer’s. 

Congrats Wei and Maysam!

Congratulations to Hrvoje Petek and his team for their paper “Plasmonically assisted channels of photoemission from metals,” which was recently selected as an Editor’s Choice by APS Physics! Their research focuses on nonlinear photoemission spectra from Ag surfaces and single- and multiplasmon excitations. Check out the abstract here! 

A team of researchers led by Jeremy Levy and several PQI members recently published a paper in Nature describing how the Kronig-Penney model is reproduced within a programmable oxide material. Introduced in 1931, this model shaped our understanding of materials that are used to create computers and other technology. 

Using an atomic force microscope, lead author Megan Briggeman created an artificial one-dimensional lattice of buckets and discovered that placing electrons in it caused them to interact in unexpected ways. In some sense, they acted as though the charge carriers were fractions of an electron. The observed behavior extends far beyond the simple Kronig-Penney model and appears in the real system, which contains hundreds of electrons.

The research was part of a larger effort to produce new electronic states of matter that may be helpful in developing future technologies such as quantum computers.

Congrats Jeremy, Megan, and team!