Research Interests: Dr. Boris Kiefer

I gratefully acknowledge current funding through:
NSF and DOE

Depending on the nature of the problem and the research objectives I use different techniques: For research problems that require insights into electronic structure I use DFT based method. The major advantage of the DFT method is that it makes no assumption about the nature of bonding in materials. Thus, DFT is versatile can treat heterogeneous bond networs and provides a unified framework for the treatment of solids, liquids, and molecules. However, a limitation of the current implementations of DFT is that it is computational too demainding too treat systems that are larger than a few hundred atoms effectively. In order to bridge the gap to larger systems we use effective potentials that lead to a speed-up of several orders of magnitude and allow to treat thousands of atoms at a comparatively small computational cost.

International Energy Outlook 2010 (U.S. Energy Information Administration, 2010)

My first interest in this research area dates back several years. I was teaching an intro course for non-science majors. Usually toward the end of the semester after Thanksgiving and before Finals week, I take some time (if possible) and address some issue that puts the class in context of society and societal development. One year I chose fossil fuels and we had a lively in-class discussion about energy, energy security, time-scales of oil formation, oil resources, the geological history of some of the reservoirs (I would like to stress that these lectures are strictly voluntary, with an average attendance rate of ~60-90%. Furthermore, these lectures are not meant to tell the students what to think. Exactly the opposite: it is intended to give the students an opportunity to voice their opinions and to integrate the course material with their previous knowledge more directly). I'd like to think of these lectures/discussions as an important component of learning since it allows to show the connectivity between differnt STEM areas.

To make the already long story short(er): I started to think, what will the fuel portfolio look like in 50 years? It is an impossible task to give a reliable answer to this question, at least I can't. Yet, we need to think about the declining fossil fuel resources, energy independence and security, global warming, and the reduction of carbon emissions. After some reflections, estimations, and reading, I realized that the fuel portfolio will be most likely more diverse than it is as present, and that we have to find fuels that are at least carbon-neutral. May be this result is not surprising but there is a difference between an opinion and a scientific argument. As an example consider the fuel distribution system at a gas station: Can it handle hydrogen as a fuel? Or for an electric car, how long am I willing to wait at a gasstation to re-charge my car? These and similar questions will determine the energy technology of tomorrow. After more reading, I started to conduct initial research into energy conversion systems with a current focus on the exploration, formulation, and optimzation of catalytic materials, in the areas of non-Pt catalysis, bimetallics, conducting oxides, and carbon supports, this effort is currently funded through DOE-EPSCoR as part of the Center for Emerging Energy Technologies which is housed at the University of New Mexico.

Sometimes teaching can give us new inspirations for research. I think research in energy science is exciting, forward looking and significant. It also has enriched my teaching, with an almost endless possibility of student projects at all levels of expertise.

Moore's law and miniaturization. Smallest linear feature size in device (left) and corrsponding number of Si atoms on a linear string of the same length (right).

Interested in the limits of information exchange, Schroedinger's cat, the Einstein-Rosen-Podolsky pardox, non-locality and the Bell inequalities? May be then this is for you:
One of the most fascenating problems in science and technology is miniaturization. More than 100 years ago, Ernest Rutherford postulated that atoms are mainly empty space, in order to explain the famous goldfoil experiment of Geiger and Marsden (1911). Richard Feynman in a lecture entitled "there's plenty of space at the bottom" made this notion much more explicit. Following one the examples from his lecture is the estimation of the size of a device that can store the content of all the books ever written. May be somewhat surprising using spin-1/2 particles it turns out that everything can be fit on a small pinhead. This thought experiment shows the potential for miniaturization if at least some of the space between atoms could be squeezed out a material. A well-known area of ongoing miniaturization are microprocessors and a natural question to ask is if there are limits to this process. Moore's law for microprocessors shows that the density of integrated circuit elements doubles every 2 years or so. Thus, eventually the densities will get so high that distances between the elements are smaller than the size of atoms which marks a natural limit to miniaturization. However, may be it is possible to reset this inescapable barrier by designing materials with "near speed of light electronics". Neglecting technological challenges such as heat conduction and contact voltages this would allow conduction to be up to 150 times faster than traditional electronics and devices to be larger. Another possibility to bypass Moore's law is to base computing on a technology that is not semiconductor based. The buzzword is spintronics. Halfmetals are a very promising class of materials for spintronic applications: one spin-channel behaves like a metal while the other spin-channel behaves like a semiconductor. A spin-polarized electron in the metallic channel can polarize the electronic spin in the semiconducting channel by exchanging angular momentum. Thus, the semiconducting spin-channel can sense and store information in response to the passing electron. The electron spin with its two orientations suggests that it is possible to encode zero's and ones's and it should not be too surprising that there is a close connection between spintronics and quantum computing. The interest in my group is in using techniques from computational materials science to search for compounds that are suitable for "near speed of light electronics" and spintronics applications.

An interesting corollary to spintronics materials may be the notion that the electron spin is restricted to teo states. Consider the nuclear spin which could have more orientations and hence store more complex information than up and down which may offer an extension to "classical" aritotelean binary logic. However, ws so many times: writing this is easy making it happen is much more difficult.

Radial structure of the Earth's interior (courtesy Dr. Garnero, ASU).

One of the most important unresolved problems in Earth Sciences remains the detailed understanding of the connection between the dynamical processes in the earth's interior and observations on the earth's surface. This endeavor requires a multidisciplinary approach of many different branches of earth's sciences such as mineral physics, seismology, geodynamics, geochemistry and petrology. Mineral physics is an essential and integral part of this challenge, it provides the link between direct observations and our understanding of the transport of mass, momentum and energy across the earth's interior. However, it is clear that all these disciplines need to come together to formulate a consistent compositinal model for the earth's interior, especially as we try to derive models for the chemical make-up and the properties of deeper (more remote) regions within our and other planets.

My interest is in understanding the composition of the chemistry of the earth's inner core, the innermost ~1225 km of our planet. Different lines of evidence, such as cosmochemistry, iron meteorites, elemental abundance, and stability of nucleii suggest that the core is composed of an iron-rich (Fe,Ni) alloy. However, this alloy is expected to be too dense at inner core pressure and temperature conditions. Thus, one or more light elements are needed to reduce the density of the (Fe,Ni) alloy and to allow reconilation of observations and laboratory experiments. Unfortunately, the nature of the light element(s) is no easy to determine at least for two reasons: 1) most of these elements will likely be retained in the liquid outer core; 2) the low abundance of the light element makes it hard to detect remotely. Thus, in-situ probes such as laboratory experiments and first-principle modeling provide important constraints for the structure of this most remote region in our planet.

Over the past few years most of the assumptions have been called into question. At low pressures iron condenses in the bcc structure. Above ~13-20 GPa bcc transforms to hcp which than remains stable to pressure that encompss the pressure at the center of the center of the earth. At high temperature and at hcp-iron transforms to fcc-iron. At high temperatures hcp-iron transforms into fcc-iron. However, experiments and some theory show, that this picture could be altered largely at high pressures and high temperature, and the dominating structure in the earth's inner core could be of bcc-, fcc-, or hcp-type. Thus, it is not even clear what the reference state is for the investigation of the light light element.

Current research in my group aims at restoring this reference state and to use first-principle computations to provide new constraints for the chemistry of the earth's inner core, which may also give clues as to oxidation or reducing conditions at the time of core formation.