Michael Demkowicz of Structure/Property Relations, Ki–Yong Kim of the Center for Nanotechnology, and Pinaki Sengupta of Condensed Matter and Statistical Physics and the National High Magnetic Field Laboratory received Postdoctoral Distinguished Performance Awards for outstanding work.
In addition to recognizing work by Lab postdocs that significantly impacts the Laboratory’s programmatic scientific efforts and status in the scientific community, these annual awards also reward unusual creativity, innovation, or dedication and level of performance above and beyond the expected.
The postdocs received a certificate and monetary award and discussed their work at a colloquium Tuesday in the Physics Building Auditorium.
Michael Demkowicz
Demkowicz was a Director’s Postdoctoral Fellow before becoming a technical staff member. He is recognized for his work in explaining mechanisms that enable high radiation damage tolerance in certain nanolayered composites.
Particle irradiation, such as in a nuclear reactor, introduces damage in a material. Demkowicz used computer simulations to study how interfaces between dissimilar materials (such as copper and niobium) attract, absorb, and annihilate these radiation-induced defects. By determining that interfaces may possess an affinity for defects, Demkowicz was able to remove defects that would otherwise have caused embrittlement and loss of mechanical integrity.
Demkowicz’s work has provided valuable insights on how to strengthen atomistic structures of the interface and achieve substantial improvements in radiation damage tolerance.
“Mike's atomistic modeling work has resulted in a new paradigm of atomic-scale design of interfaces in nano-composite materials for radiation damage tolerance and will be of great significance for the development of structural materials for the next generation of nuclear power reactors,” said Amit Misra of the Center for Integrated Nanotechnologies (MPA-CINT), who nominated Demkowicz for the award.
Demkowicz, who obtained a doctorate in mechanical engineering from Massachusetts Institute of Technology, is one of the founding members of the Los Alamos Postdoctoral Association serving as both vice-president and president.
Ki-Yong Kim
Kim, a previous Director’s Postdoctoral Fellow and current postdoctoral research associate, was recognized for his achievements in the development of ultrafast terahertz (THz) radiation as a single-shot diagnostic to study electronic transport properties of materials, warm dense plasmas, dynamic strain and shocks, and for characterization of short pulse electron bunches generated from intense laser-based electron accelerators.
Kim has investigated time-resolved phase transitions of intense ultrashort laser-heated materials from the cold, solid phase to the warm, dense-plasma state and developed a new gas plasma-based table-top source of THz radiation. His experiments showed for the first time the generation of tunable coherent light in the range of 1 to 100 THz.
Kim’s work, described by renowned scientists in the field as "seminal," "innovative," and "exceptionally creative," has been published in premier scientific journals, including Physical Review Letters and Nature Photonics (in press). His research will leave a lasting scientific legacy in the area of ultrafast time-resolved materials and plasma dynamics.
“At every opportunity to contribute to the field, Ki-Yong has sought to efficiently and convincingly present scientific results that advance our understanding of complex physics through concise and innovative experimental approaches,” said George Rodriguez of CINT, who nominated Kim for this award.
Kim obtained his doctorate in physics at the University of Maryland.
Pinaki Sengupta
Sengupta, a postdoctoral research associate, has made several important contributions to quantum magnetism theory. Sengupta explained the origin of a novel sequence of magnetization plateaus in a magnetic insulator known as “Shastry-Sutherland compound” that were previously measured by Suchitra Sebastian (Cambridge) and Neil Harrison of Los Alamos.
Sengupta's original approach, based on an unconstrained Chern-Simons mean field theory, reproduced the whole sequence of measured plateaus. The spin textures that were subsequently predicted from the same theory have now been observed in the new Shastry-Sutherland compound. He also demonstrated that a magnetic-field-induced spin supersolid phase can be realized in simple spin lattice models. This proposal has motivated a search for materials that will exhibit this novel phase. Finally, Sengupta proposed a simple but powerful theory for computing the magnetostriction of quasi-one dimensional magnets.
Sengupta’s theoretical work has significantly contributed to the quantitative microscopic understanding of physics of quantum magnets and established connections to other seemingly distinct collective phenomena in condensed matter.
"The extraordinary performance of Pinaki during his post-doctoral appointment at LANL lies on the combination of outstanding virtues such as hard work, strong will, and a markedly humble personality,” said Cristian Batista, who, together with Marcelo Jaime of the National High Magnetic Field Laboratory (MPA-NHMFL), nominated Sengupta for this award. “Consequences of these virtues are his fruitful collaborations with the NHMFL-LANL and his original contributions to the theory of quantum magnets that were stimulated by the Center for Nonlinear Studies and Condensed Matter and Statistical Physics environments. By bridging our theoretical and experimental efforts, Pinaki showed a way of exploiting and expanding unique capabilities that we have at LANL."
Sengupta obtained his doctorate in physics at the University of Illinois-Urbana. He also received an honorable mention for this year’s Leon Heller Postdoctoral Publication Prize in Theoretical Physics.
Laboratory staff nominate postdocs for the Postdoctoral Distinguished Performance Award. The nominations are forwarded to a committee of senior technical staff members who then review each nominee before submitting their final recommendations to the Laboratory director for approval.
