The Minerals, Metals & Materials Society's Bardeen Award, established in l994 recognizes an individual who has made outstanding contributions and is a leader in the field of electronic materials.
Alex Zunger- citation:
For his seminal contributions to the theoretical understanding and prediction of "spontaneous ordering," phase-stability, and electronic properties of semiconductor alloys; for the impact that this work has had on experimental studies of electronic materials, and for his continued leadership in the field.
Explanation of the physics:Bulk semiconductor alloys such as (GaP)x(InP)1-x are known to exhibit a repulsion between the constituents, so they were never expected to order crystallographically. Indeed, they were known to form random structures at high temperatures and phase-separation at low temperatures. Theory has shown, however, that "surface reconstruction"--an almost universal feature of covalent surfaces--can lead to an ordered atomic arrangement in alloys since the alternative, (random configuration) is highly strained by surface dimers. Thus, strain-minimizing surface-stable ordered structures are frozen in-by the growth process. The lower symmetry of ordered structures relative to random alloys leads to profound changes in band gaps, optical selection rules, effective-masses, pressure dependence and transport properties, predicted by Zunger and his group starting in l984. Ordering has since been discovered in virtually all covalent semiconductor alloys. For more details see http://www.sst.nrel.gov/topics/alloy_order.html. These effects, plus the fact that control of ordering creates new, technologically-significant materials properties has led to >1000 experimental publications in this field.
Biography: Alex Zunger is an Institute Research Fellow and leader of the Solid State Theory at the U. S. Department of Energy's National Renewable Energy Laboratory (NREL). He received his B. Sc, M.Sc and Ph.D education at the Tel Aviv University, Israel (PhD: l976 in chemical physics), and did his post-doctoral training at Northwestern University, Evanston, Ill. (l975-l977) and (as IBM Fellow) University of California, Berkeley (l977-l978). He joined the newly founded NREL in l978 where he established the Solid State Theory group and trained and collaborated, since, with 35 post-doctoral fellows. He is an author of 400 journal publications, including over 85 in Physical Review Letters and Rapid Communication. According to recent research done by the Institute of Scientific Information (ISI), he is the 39th most cited physicist out of more than 500,000 physicists examined, based on publications in l981-l997 in all branches of physics (his work was cited-8, 000 times). His work centers on development and application of "First-Principles" electronic structure theory of "real materials". It includes the development of "first-principles Pseudopotentials; accurate exchange-correlation functionals; the momentum-space total energy formalism; simultaneous relaxation of atomic positions and electronic wave functions; "order N" electronic structure approaches, and "cluster expansions" for alloy thermodynamics. These techniques were applied by him to metal alloys, quantum semiconductor nanostructures. points defects and surfaces.
Quote: "I am honored and would like to thank my NREL post-docs and staff for exciting collaborations on this project: J Bernard, A. Franceschetti, S. Froyen, D Laks, K. Mader, R. Magri, J. L. Martins, T. Matilla, A. Mbaye, R. Osorio, V. Ozolins, G. P. Srivastava, D. M. Wood, S. H. Wei and S. B. Zhang."