@article{paesler_kastner_rosenbaum_2018, title={Hellmut Fritzsche OBITUARIES}, volume={71}, ISSN={["1945-0699"]}, DOI={10.1063/PT.3.4028}, abstractNote={In a letter he wrote in June 2018, the month of his passing, Hellmut Fritzsche, professor emeritus at the University of Chicago, reflected on his life and marriage: “[My wife] Sybille and I were so very fortunate to have been selected in 1950 to the group of European students who were invited by the US government to come to the United States for one year. This is how we met. How immensely admirable was the generosity of the United States! We both had a rich and rewarding life. We are grateful for the opportunities given to us and for the wonderful life and inspiring circle of friends who questioned and supported us intellectually.” Those of us in that circle were richly rewarded for having experienced Hellmut’s inquisitive mind and vibrant nature. Hellmut Fritzsche PPT|High resolutionBorn on 20 February 1927 in Berlin, Hellmut received his diplom in physics from the University of Göttingen in 1952. He went to the US and earned his PhD at Purdue University in 1954; working with Karl Lark-Horovitz, he studied the electrical properties of semiconductors. In 1957 he moved to the University of Chicago, where he remained until his retirement in the late 1990s.Hellmut’s impressive early experiments at Chicago involved creating samples of germanium doped by transmutation of one isotope into gallium and another into arsenic. He used the samples to study the motion of electrons in impurity bands; the isotope ratio determines the precise “compensation” ratio of acceptors to donors. That research laid the groundwork for much of our understanding of electron motion in disordered systems: The known compensation allowed him to isolate the effects of disorder from those of electron–electron interaction when electrons tunnel between localized states. The same issues were central to understanding the behavior of electrons in amorphous semiconductors, a subject in which Hellmut became the foremost experimenter.In the mid 1960s, Hellmut was introduced by John Bardeen to Stanford Ovshinsky, a self-educated industrial scientist and founder of Energy Conversion Devices (ECD). While maintaining his faculty position at Chicago, Hellmut guided much of ECD’s innovative research, which led to important products—including electronic and optical memory devices, solar cells, and batteries—that use amorphous materials. His enthusiasm for seeing scientific discovery translated into technology was an inspiration to his students at a time when many universities avoided that connection.Hellmut took particular pride in his ability to derive innovative experimental solutions for problems he confronted. For example, he conceived a means of using a simple ball valve to control alternating gases in a multicomponent deposition system. While in India visiting colleagues with meager resources, he designed and built a vacuum system from available kitchenware. And to gently remove self-supporting thin-film samples from substrates, he devised an instrument to float the film onto the surface of a solvent.Starting in 1977 Hellmut chaired Chicago’s physics department for almost a decade. His commitment to research excellence was complemented by his single-minded devotion to overseeing the building of the Kersten Physics Teaching Center, down to the design of the classrooms and the choice of furniture in the interactive spaces. As chair, Hellmut emphasized the recruitment of junior faculty. He created a vibrant intellectual atmosphere and made sure that new recruits were introduced to the cultural riches of Chicago. It was a family effort, with Hellmut and Sybille making their home the academic and social nexus of Chicago’s Hyde Park neighborhood.Hellmut and Sybille were an amazing team. While he was leading the field of amorphous semiconductors, she earned a law degree at the University of Chicago and became an influential civil rights lawyer before earning a PhD in Chinese history. The two were voracious readers, and sharing a meal with them was an intellectual feast as well.Hellmut and Sybille remained physically active into their nineties. They kayaked and swam at their beloved summer home on New Hampshire’s Lake Winnipesaukee as late as the summer of 2017. The letter quoted above provided a coda to their lives prior to their deaths on 17 June 2018. It concluded, “Now we have come to the end of our lives. We wish to avoid the painful and frustrating period of agonizing death with the often occurring changes in personality, supported by the latest advances of medicine. We both decided to end our lives with dignity. That is what we have done and this letter is our farewell.”All who knew Hellmut can understand how the grace and dignity of the end of his life only underscores the many ways he taught us about how to live productively and joyously until we, too, bid farewell.© 2018 American Institute of Physics.}, number={9}, journal={PHYSICS TODAY}, author={Paesler, Michael and Kastner, Marc and Rosenbaum, Thomas F.}, year={2018}, month={Sep}, pages={67–67} }
 @article{washington_joseph_raoux_jordan-sweet_miller_cheng_schrott_chen_dasaka_shelby_et al._2011, title={Characterizing the effects of etch-induced material modification on the crystallization properties of nitrogen doped Ge2Sb2Te5}, volume={109}, ISSN={["1089-7550"]}, DOI={10.1063/1.3524510}, abstractNote={The chemical and structural effects of processing on the crystallization of nitrogen doped Ge2Sb2Te5 is examined via x-ray photoelectron spectroscopy (XPS), x-ray absorption spectroscopy (XAS), time resolved laser reflectivity, and time resolved x-ray diffraction (XRD). Time resolved laser reflectivity and XRD show that exposure to various etch and ash chemistries significantly reduces the crystallization speed while the transition temperature from the rocksalt to the hexagonal phase is increased. XPS and XAS attribute this to the selective removal and oxidization of N, Ge, Sb, and Te, thus altering the local bonding environment to the detriment of device performance.}, number={3}, journal={JOURNAL OF APPLIED PHYSICS}, author={Washington, J. S. and Joseph, E. A. and Raoux, S. and Jordan-Sweet, J. L. and Miller, D. and Cheng, H. -Y. and Schrott, A. G. and Chen, C. -F. and Dasaka, R. and Shelby, B. and et al.}, year={2011}, month={Feb} }
 @article{lucovsky_washington_miotti_paesler_2010, title={Analysis of the forgotten parts of the Ge K edge spectra: life before the EXAFS oscillations}, volume={7}, ISSN={["1862-6351"]}, DOI={10.1002/pssc.200982887}, abstractNote={Abstract}, number={3-4}, journal={PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 7 NO 3-4}, author={Lucovsky, Gerald and Washington, Joseph P. and Miotti, Leonardo and Paesler, Michael}, year={2010}, pages={844–847} }
 @inproceedings{washington_josep_paesler_lucovsky_jordan-sweet_raoux_chen_pyzyna_dasaka_schrott_et al._2009, title={The influence of nitrogen doping on the chemical and local bonding environment of amorphous and crystalline Ge2Sb2Te5}, volume={1160}, DOI={10.1557/proc-1160-h13-08}, abstractNote={Abstract}, booktitle={Materials and physics for nonvolatile memories}, author={Washington, J. S. and Josep, E. and Paesler, M. A. and Lucovsky, G. and Jordan-Sweet, J. L. and Raoux, S. and Chen, C. F. and Pyzyna, A. and Dasaka, R. K. and Schrott, A. and et al.}, year={2009}, pages={163–168} }
 @article{agarwal_paesler_baker_taylor_lucovsky_edwards_2008, title={Bond constraint theory and the quest for the glass computer}, volume={70}, ISSN={["0973-7111"]}, DOI={10.1007/s12043-008-0043-y}, number={2}, journal={PRAMANA-JOURNAL OF PHYSICS}, author={Agarwal, S. C. and Paesler, M. A. and Baker, D. A. and Taylor, P. C. and Lucovsky, G. and Edwards, A.}, year={2008}, month={Feb}, pages={245–254} }
 @article{paesler_baker_lucovsky_2008, title={Bond constraint theory studies of chalcogenide phase change memories}, volume={354}, DOI={10.1016/j.jnoncryso1.2007.09.045}, number={19-25}, journal={Journal of Non-crystalline Solids}, author={Paesler, M. A. and Baker, D. A. and Lucovsky, G.}, year={2008}, pages={2706–2710} }
 @article{paesler_baker_lucovsky_taylor_washington_2007, title={Bond constraint theory and EXAFS studies of local bonding structures of Ge2Sb2Te4, Ge2Sb2Te5, and Ge2Sb2Te7}, volume={9}, number={10}, journal={Journal of Optoelectronics and Advanced Materials}, author={Paesler, M. A. and Baker, D. A. and Lucovsky, G. and Taylor, P. C. and Washington, J. S.}, year={2007}, pages={2996–3001} }
 @article{paesler_baker_lucovsky_edwards_taylor_2007, title={EXAFS study of local order in the amorphous chalcogenide semiconductor Ge2Sb2Te5}, volume={68}, ISSN={["1879-2553"]}, DOI={10.1016/j.jpcs.2007.03.041}, abstractNote={Studies of amorphous (a-) semiconductors have been driven by technological advances as well as fundamental theories. Observation of electrical switching, for example, fueled early interest in a-chalcogenides. More recently switching of the a-chalcogenide Ge2Sb2Te5 has been applied quite successfully to DVD technology where the quest for the discovery of better-suited materials continues. Thus, switching provides researchers today with an active arena of technological as well as fundamental study. On the theoretical front, bond constraint theory — or BCT — provides a powerful framework for understanding the structure and properties of a-materials. Applications of BCT to switching in Ge2Sb2Te5 holds the promise of finding the best composition suited for switching applications. This work presents EXAFS data that describe local bonding configurations in as-deposited Ge2Sb2Te5. The data show that Ge2Sb2Te5 may best be viewed as a random array of Ge2Te3 and Sb2Te3 structural units imbedded in a tissue of a-Te, 17% of which is over coordinated. In addition, a valence alternation pair defect is introduced to the model to satisfy charge conservation constraints.}, number={5-6}, journal={JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS}, author={Paesler, M. A. and Baker, D. A. and Lucovsky, G. and Edwards, A. E. and Taylor, P. C.}, year={2007}, pages={873–877} }
 @article{lucovsky_baker_paesler_phillips_thorpe_2007, title={Intermediate phases in binary and ternary alloys. How far can we go with a semi-empirical bond-constraint theory?}, volume={9}, number={10}, journal={Journal of Optoelectronics and Advanced Materials}, author={Lucovsky, G. and Baker, D. A. and Paesler, M. A. and Phillips, J. C. and Thorpe, M. F.}, year={2007}, pages={2979–2988} }
 @article{baker_paesler_lucovsky_2007, title={Local bonding arrangements in amorphous Ge2Sb2Te5: the importance of Ge and Te bonding}, volume={18}, ISSN={["1573-482X"]}, DOI={10.1007/s10854-007-9233-5}, journal={JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS}, author={Baker, D. A. and Paesler, M. A. and Lucovsky, G.}, year={2007}, month={Oct}, pages={S399–S403} }
 @article{lucovsky_baker_paesler_phillips_2007, title={Spectroscopic and electrical detection of intermediate phases and chemical bonding self-organizations in (i) dielectric films for semiconductor devices, and (ii) chalcogenide alloys for optical memory devices}, volume={353}, ISSN={["1873-4812"]}, DOI={10.1016/j.jnoncrysol.2007.01.041}, abstractNote={This paper presents a discussion of intermediate phases in thin film materials that have been incorporated into liquid crystal displays, LCDs, and optical memory thin film devices. The formation of intermediate phases in the a-Si3N4:H (a-Si:N:H) alloys used for gate dielectrics in thin film transistors, TFTs, of LCDs, and the a-Ge–Sb–Te (GST) alloys used for read-write optical writing and storage in optical memory discs are qualitatively different than those first addressed by the Boolchand group in Ge–Se bulk glass alloys. In the a-Si:N:H and a-GST thin films, the chemical self-organizations that suppress percolation of strain, involve chemically-ordered bonding arrangements that break bond bending constraints at the four-fold coordinated Si and Ge atoms in a-Si:N:H and a-GST, respectively. In the GST alloys, this results in over-coordinated and under-coordinated atomic constituents, or valence alternation pairs, VAPs, of charged defects. Finally, other technologically important systems in which broken constraints, and/or VAP defects are important in intermediate phase formation include group IVB (Ti, Zr and Hf) Si oxynitride alloys, and hydrogenated amorphous Si (a-Si:H).}, number={18-21}, journal={JOURNAL OF NON-CRYSTALLINE SOLIDS}, author={Lucovsky, G. and Baker, D. A. and Paesler, M. A. and Phillips, J. C.}, year={2007}, month={Jun}, pages={1713–1722} }
 @article{baker_paesler_lucovsky_agarwal_taylor_2006, title={Application of bond constraint theory to the switchable optical memory material Ge2Sb2Te5}, volume={96}, ISSN={["0031-9007"]}, DOI={10.1103/physrevlett.96.255501}, abstractNote={A new extended x-ray-absorption fine structure spectroscopy study of local bonding identifies for the first time significant concentrations of Ge-Ge bonds in amorphous Ge2Sb2Te5. The study provides a new understanding of the local molecular structure of this phase-change material. Application of bond constraint theory indicates that the amorphous phase is an ideal network structure in which the average number of constraints per atom equals the network dimensionality. Analysis within this framework imparts new and significant insights concerning the nature of the reversible optically driven amorphous-crystalline phase transition of Ge2Sb2Te5.}, number={25}, journal={PHYSICAL REVIEW LETTERS}, author={Baker, DA and Paesler, MA and Lucovsky, G and Agarwal, SC and Taylor, PC}, year={2006}, month={Jun} }
 @article{baker_paesler_lucovsky_taylor_2006, title={EXAFS study of amorphous Ge2Sb2Te5}, volume={352}, ISSN={["1873-4812"]}, DOI={10.1016/j.jnoncrysol.2005.11.079}, abstractNote={Extended X-ray absorption fine structure (EXAFS) studies of sputtered amorphous pristine thin films of Ge2Sb2Te5 reveal only four of the six possible bond pairs. That is, we find no successful fit to EXAFS data showing Ge–Sb or Te–Te bonds. Furthermore, our data indicate Ge is fully four-fold coordinated (N = 4) while both Sb and Te are over-coordinated with respective N values of 3.3 and 2.4. In Ge–Sb–Te alloys we note that the difference in magnitude of the optical transmissivity between the amorphous and crystalline states of is proportional to the fraction of three-fold coordinated Te.}, number={9-20}, journal={JOURNAL OF NON-CRYSTALLINE SOLIDS}, author={Baker, D. A. and Paesler, M. A. and Lucovsky, G. and Taylor, P. C.}, year={2006}, month={Jun}, pages={1621–1623} }
 @article{paesler_baker_lucovsky_edwards_taylor_2006, title={EXAFS study of local order in the amorphous chalcogenide semiconductor Ge2Sb2Te5}, volume={8}, number={6}, journal={Journal of Optoelectronics and Advanced Materials}, author={Paesler, M. A. and Baker, D. A. and Lucovsky, G. and Edwards, A. E. and Taylor, P. C.}, year={2006}, pages={2039–2043} }
 @article{paesler_stern_thomlinson_2005, title={Dale Edward Sayers - Obituary}, volume={58}, ISSN={["0031-9228"]}, DOI={10.1063/1.2012482}, abstractNote={Dale Edward Sayers, a professor of physics at North Carolina State University who made pioneering contributions in x-ray spectroscopy, died on 25 November 2004 in Raleigh. He had suffered a heart attack while jogging several weeks earlier.Born on 29 November 1943 in Seattle, Washington, Dale earned his bachelor’s degree in 1966 in physics at the University of California, Berkeley, and his master’s and doctoral degrees, both in physics, in 1972 at the University of Washington, Seattle. His PhD research, completed in 1971 under the direction of one of us (Stern), centered on developing a new local-structure determination technique named extended x-ray absorption fine structure.The first EXAFS paper, which Dale wrote with Stern and Farrell Lytle in 1971, opened this new field. EXAFS became an important experimental technique for local-structure studies at synchrotron radiation sources worldwide. The researchers’ effort also led to the establishment of the International XAFS Conferences, the 12th of which convened in 2003 in Sweden. Dale was also instrumental in establishing the International XAFS Society (IXS), now a subunit of the International Union of Crystallography. The IXS organizes the International XAFS Conferences, sets standards in the field, and conducts other activities.Soon after he started his PhD research, Dale began experiments at the Boeing Scientific Research Laboratory in Seattle in collaboration with Lytle. On completing his PhD, he became a research engineer at Boeing Aerospace Co in Seattle before returning to the University of Washington as a postdoctoral research associate. In 1976 he joined the physics faculty at NC State and flourished there for the remainder of his career. Dale went on sabbatical in France as a visiting professor at the Université de Paris–Sud in Orsay from 1982 to 1983 and at the Université Joseph Fourier in Grenoble in 1996. He also was a visiting scientist at the European Synchrotron Radiation Facility in Grenoble in 2000 and the Advanced Light Source in Berkeley, California, in 2000.A master in the art of collaboration, Dale had wide-ranging scientific interests, from his primary focus on the applications of synchrotron-radiation-based techniques to the study of complex materials. He applied the EXAFS technique to studying many systems, including amorphous alloys, the semiconductor–metal interface, catalysts, electrochemical systems, environmentally contaminated systems, and metalloproteins. Other techniques that he developed and used were anomalous scattering and x-ray diffraction, fluorescence microprobe, and microscopy. In 1995 he was part of a team that discovered a new x-ray imaging modality called diffraction enhanced imaging, or DEI. Shortly before his death, Dale had been investigating the potential of DEI in medical research as a clinical tool for mammography, osteoarthritis, and bone density studies.In recognition of his many accomplishments, Dale received international and local research awards. In 1979 he shared the American Crystallographic Association’s Bertram E. Warren Diffraction Physics Award with Lytle and Stern, and he won the IXS’s Outstanding Achievement Award in 2003.Dale’s genius lay in his ability to apply the right techniques to the problem at hand. That skill manifested itself in his administrative roles in the department, college, university, and international research community. His colleagues often viewed him as a sort of “WD-40” that one could spray on problems or situations that were stuck and needed help to gain momentum. A member of innumerable committees, Dale was a highly valued source of reason who recognized what should be done and directed forces toward the reality of what could be done.Dale quickly developed and thoughtfully nurtured relationships with a host of colleagues and was known as a clever raconteur. He loved to travel and dine, and reveled in the fact that his research took him to synchrotrons far and wide, where at the end of a day of research, he could socialize while enjoying escargots in Orsay, bratwurst in Berlin, or borscht in Dubna. Dale thrived in academe: He delighted in being a mentor to students, a supporter of junior faculty, and a team player who could use his many skills to advance causes and projects in which he believed.The breadth of his contributions and the warmth of his character magnify the loss of our dear friend and colleague.© 2005 American Institute of Physics.}, number={7}, journal={PHYSICS TODAY}, author={Paesler, M and Stern, E and Thomlinson, W}, year={2005}, month={Jul}, pages={82–82} }
 @misc{russell_paesler_2003, title={Environments of Mid-Cretaceous Saharan dinosaurs}, volume={24}, ISSN={["1095-998X"]}, DOI={10.1016/S0195-6671(03)00072-7}, abstractNote={Recent studies of the oceanic record suggest that the Earth was a global greenhouse during middle Cretaceous time. A review of topographic, sedimentary and biologic data pertaining to terrestrial mid-Cretaceous equatorial environments broadly supports the climatic inferences of marine studies. In particular, analyses of widely-occurring low latitude Saharan sediments support the Cretaceous greenhouse hypothesis. In comparison to marine ecosystems, terrestrial ecosystems respond more sensitively to atmospherically transported heat and nutrients because of the more tenuous presence of the hydrosphere on land. Indeed, the morphologies of terrestrial biota suggest that: (1) equatorial mid-Cretaceous climates were episodic rather than seasonal; (2) convective storms although infrequent were violent; and (3) a moist intertropical convergence zone was absent. Cretaceous atmospheric dynamics apparently differed importantly from those of the present. Circumstantial evidence suggests that (1) higher atmospheric carbon dioxide levels probably stimulated the emission of other greenhouse gases; and (2) higher humidity levels reduced diurnal temperature variations but impaired evaporative thermoregulatory mechanisms. That terrestrial ecosystems withstood greenhouse conditions in low latitudes as well as they did underscores the adaptability of terrestrial life. Analogies for future environmental stresses and responses, whether anthropogenic or resulting from other causes, might be found in the terrestrial record of the Cretaceous equatorial zone.}, number={5}, journal={CRETACEOUS RESEARCH}, author={Russell, DA and Paesler, MA}, year={2003}, month={Oct}, pages={569–588} }
 @article{ayars_jahncke_paesler_hallen_2001, place={UK}, title={Fundamental differences between micro- and nano-Raman spectroscopy}, volume={202}, ISSN={["0022-2720"]}, url={http://dx.doi.org/10.1046/j.1365-2818.2001.00878.x}, DOI={10.1046/j.1365-2818.2001.00878.x}, abstractNote={Electric field polarization orientations and gradients close to near‐field scanning optical microscope (NSOM) probes render nano‐Raman fundamentally different from micro‐Raman spectroscopy. With x‐polarized light incident through an NSOM aperture, transmitted light has x, y and z components allowing nano‐Raman investigators to probe a variety of polarization configurations. In addition, the strong field gradients in the near‐field of a NSOM probe lead to a breakdown of the assumption of micro‐Raman spectroscopy that the field is constant over molecular dimensions. Thus, for nano‐Raman spectroscopy with an NSOM, selection rules allow for the detection of active modes with intensity dependent on the field gradient. These modes can have similar activity as infra‐red absorption modes. The mechanism can also explain the origin and intensity of some Raman modes observed in surface enhanced Raman spectroscopy.}, number={1}, journal={JOURNAL OF MICROSCOPY-OXFORD}, author={Ayars, EJ and Jahncke, CL and Paesler, MA and Hallen, HD}, year={2001}, month={Apr}, pages={142–147} }
 @inbook{ayars_paesler_hallen_2000, title={Near-field Raman spectroscopy: electric field gradient effects}, volume={165}, ISBN={0750306858}, number={2000}, booktitle={Microbeam Analysis 2000: proceedings of the Second Conference of the International Union of Microbeam Analysis Societies held in Kailua-Kona, Hawaii, 9-14 July 2000}, publisher={Bristol: Institute of Physics Publishing}, author={Ayars, E. J. and Paesler, M. A. and Hallen, H. D.}, editor={Williams, D. B. and Shimizu, R.Editors}, year={2000}, pages={115–116} }
 @article{paesler_2000, title={Papers from the International Conference on Silicon Dielectric Interfaces - 25-27 February 2000 - Raleigh, North Carolina - Preface}, volume={18}, number={3}, journal={Journal of Vacuum Science & Technology. B, Microelectronics and Nanometer Structures}, author={Paesler, M.}, year={2000}, pages={1736} }
 @article{ayars_aspnes_moyer_paesler_1999, title={Proximal electromagnetic shear forces}, volume={196}, DOI={10.1046/j.1365-2818.1999.00596.x}, abstractNote={We perform a simple model calculation to estimate the electromagnetically induced shear force caused by a current dissipation when a charged tip is moved parallel to a conducting material. For parameters typical in shear force imaging, the force is many orders of magnitude below reported values. Thus, proximal electromagnetic tip–sample forces can be neglected in discussions of shear force imaging.}, number={1}, journal={Journal of Microscopy}, author={Ayars, E. and Aspnes, D. E. and Moyer, P. and Paesler, M. A.}, year={1999}, pages={59–60} }