Visiting Professor, Hanover College (2003)
Postdoc, Georgia Tech (2001)
Postdoc, UC Davis (1997)
Ph.D., University of Illinois (1994)
B.A., Columbia University (1984)
Computational Physics; Condensed Matter Physics; Conceptual Physics for nonscience majors; Electricity and Magnetism; Graduate-level education
Fundamentals of Density Functional Theory (DFT)
One of the most consequential laws of quantum physics is that there exists a direct, unique map between the electron density of any electronic system and its ground-state energy and other electronic properties. The exact nature of this map is not known -- this would need the equivalent of the knowing the solution to every quantum electronic system possible -- not only molecules, solids or nanostructures, but systems like million-electron atoms that exist in mathematics alone. Having accurate approximations for this connection gives researchers a tool for performing quick but accurate approximate solutions for the properties of electronic systems, bypassing the intractable many-electron equations that result from the exact quantum treatment. This approach to materials simulation has a wide interdisciplinary impact. It's the ``go-to" method for modern quantum chemistry and an important tool for understanding materials at the nearly atomic scale of modern electronic devices.
The main theme of my group's research at Ball State is to build a better understanding of this basic connection between electron density and energy, and using this understanding to build better models for predicting electronic behavior. One recent focus is the kinetic energy (the energy of motion) of electrons, which we seek to model in the simplest possible fashion -- looking for orbital-free models that forgo the need for knowing individual electron orbitals that are often used in chemistry. To do this, we rely on the visualization of numerical simulation data from various sources -- eyes often find surprise connections that analytic calculations miss. Another approach is to study asymptotic trends as nuclear charge and electron population are taken to infinity. Though such ultra-heavy atoms have unstable nuclei and are not found in nature, they represent a limit case in which the physical relations between energy and density become readily apparent. Knowing more about this limit gives insights into what is important for modeling much smaller atoms.
We are also engaged in a collaboration with Dr. Mahfuza Khatun of the Physics department, exploring the electronic structure and device characteristics of two-dimensional materials. These materials, only one to a few atomic layers in thickness, exhibit many physical behaviors not seen in normal materials, and are promising candidates for novel solid-state devices. We are applying density functional techniques to the band-engineering of hBN nanoribbons and to the search for possible topogical insulator phases in bilayer and trilayer stanene -- the two-dimensional form of tin.
"Fitting a round peg into a round hole: asympotically correcting the generalized gradient approximation for correlation" Antonio Cancio, Guo P. Chen, Brandon T. Krull, Kieron Burke submitted to Journal of Chemical Physics
Abstract link: arxiv.org/abs/1801.01916
"Visualisation and orbital-free parametrisation of the large-Z scaling of the kinetic energy density of atoms," Antonio C. Cancio, Jeremy J. Redd, Molecular Physics, 115, 618 (2016).
DOI Link: dx.doi.org/10.1080/00268976.2016.1246757
"Locality of correlation in density functional theory," Kieron Burke, Antonio Cancio, Tim Gould and Stefano Pittalis, Journal of Chemical Physics, 145, 054112 (2016).
DOI Link: dx.doi.org/10.1063/1.4959126.
"Visualization and analysis of the Kohn-Sham kinetic energy density and its orbital-free description in molecules," Antonio Cancio, Dane Stewart and Aeryk Kuna, Journal of Chemical Physics, 144, 084107 (2016).
DOI Link: dx.doi.org/10.1063/1.4942016.
"Effects of Band Hybridization on Electronic Properties in Tuning Armchair Graphene Nanoribbons," M. Khatun, Z. Kan, A. C. Cancio, C. Nelson, Canadian Journal of Physics, 94, 218 -- 225, (2016).
DOI Link: dx.doi.org/10.1139/cjp-2015-0066.
"Laplacian based models of the exchange energy," A. C. Cancio, Chris E. Wagner and Shaun A. Wood, International Journal of Quantum Chemistry, 112, 3796 -- 3806, (2012).
DOI Link: dx.doi.org/10.1002/qua.24230.
"Scaling properties of exchange and correlation holes of the valence shell of second-row atoms," A. C. Cancio and C. Y. Fong, Physical Review A, 85 042515 (2012).
DOI Link: dx.doi.org/10.1103/PhysRevA.85.042515.
"Beyond the local approximation to exchange and correlation: The role of the Laplacian of the density in the energy density of Si," A. C. Cancio and M. Y. Chou, Physical Review B, 74, 081202(R) (2006).
DOI Link: dx.doi.org/10.1103/PhysRevB.74.081202.