Condensed-Matter and Materials Physics Basic Research for Tomorrow's Technology (1999) / Chapter Skim
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Pages 5-30
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From page 5... ...
Because it deals with properties of matter at ordinary chemical and thermal energy scales, condensed-matter and materials physics is the subfield of physics that has the largest number of direct practical applications. It is also an intellectually vital field that is currently producing many advances in fundamental physics.
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From page 6... ...
Technological advances provide new tools such as synchrotrons, neutron sources, electron microscopes, computers, and scanning-probe microscopes. These new tools are leading to new advances in the fundamental understanding of materials and to a wide-ranging impact on other fields biology, chemistry, environmental sciences, and engineering.
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From page 7... ...
The combined power of the new experimental tools and computational advances are having an enormous impact on condensed-matter and materials physics, particularly in those areas where the ability to span length scales from the atomic to macroscopic is of fundamental importance, that is, where the properties of atoms and molecules especially quantum phenomena become relevant to large-scale phenomena. This new capability to span length scales is bringing the world of atoms and molecules closer to the world of our experience, from the mysteries of quantum mechanics, to the mechanical properties of materials, to the self-assembly of biological systems.
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From page 8... ...
THE SCIENCE OF MODERN TECHNOLOGY The information age owes its rapid growth to technological advances that depend on progress in science. Scientific understanding of fundamental phenomena has been closely tied to the development of materials with special properties as carriers and controllers of electrical current, light waves, and magnetic fields.
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From page 9... ...
Among the sensors based on these new technologies are superconducting quantum interference devices (SQUIDs) that enable the detection of minuscule magnetic fields emitted by the human brain and heart, and magnetic force microscopes that can image magnetic properties with nearly atomic-scale resolution.
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From page 10... ...
That, in turn, led to the discovery that the electrical resistance of lanthanum manganate can be extremely sensitive to the presence of magnetic fields. This effect, known as "colossal magnetoresistance," is of great interest
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From page 11... ...
Several themes and challenges are apparent the role of molecular geometry and reduced dimensionality, the synthesis and processing and understanding of more complex materials, tailoring the composition and structure of materials on very small scales, and incorporation of new materials and structures in existing technologies. Progress in these areas holds the promise of further startling breakthroughs, yielding materials with unexpected and useful properties and extending the understanding of condensed-matter and materials physics.
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From page 12... ...
By contrast, in elementary-particle physics, the frontier is at increasingly higher energies and shorter length scales. A particularly fascinating emergent phenomenon occurs in helium at very low temperatures.
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From page 13... ...
The ratio of the applied current to this voltage has the units of a conductance (or inverse electrical resistance) and is called the "Hall conductance." If this experiment is carried out at high magnetic fields and low temperatures, quantum mechanics comes into play and the Hall conductance becomes
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From page 14... ...
14 oo a' ·_4 VO so so C)
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From page 15... ...
. An even more surprising phenomenon occurs with samples of very high purity at very low temperatures and in very high magnetic fields.
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From page 16... ...
These include pattern formation and turbulence in fluid flow, processing and performance of structural materials, and some topics in solid mechanics, specifically, friction, fracture, granular materials, and polymers and adhesives. The chapter on nonequilibrium physics also includes brief discussions of nonequilibrium phenomena in the quantum and biological domains, and yet briefer remarks about nonequilibrium complexity and limits of predictability.
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From page 17... ...
The cell provides a rich new universe of complex nonequilibrium phenomena for study by physicists. The rewards to society of detailed physical understanding of fundamental life processes could be enormous.
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From page 18... ...
By determining the structure of very large and complicated biological molecules at the atomic scale of resolution, physics is having a significant impact on biology. Most structure determination is done via x-ray diffraction from crystallized material.
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From page 19... ...
Biological molecules are made mostly of carbon, hydrogen, nitrogen, and oxygen; neutrons are particularly good probes of such light elements, providing information that is complementary to that obtained with x-ray sources. Although neutron sources in the United States are very active, the dearth of high-intensity sources here is an obstacle to progress in this area; this obstacle will be removed when the Spallation Neutron Source comes online in 2005.
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From page 20... ...
· High magnetic fields and high pressures were used to gain understanding of charge transport. Many of these studies were performed at large- or medium-scale facilities.
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synchrotron radiation source in the United States is the Advanced Photon Source (APS) at Argonne National Laboratory.
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From page 22... ...
The most rapidly growing and arguably the most important use of synchrotron radiation is in protein crystallography, in which the structure of biologically important proteins is determined. Crystallography of big molecules using synchrotrons is the primary source of insight into three-dimensional biological structures.
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From page 23... ...
Among the recent successes of neutron scattering has been the demonstration that the high-TC superconductors have a common feature nearly square planar arrays of copper and oxygen atoms. Neutron scattering also was used to image vortex lattices in high-TC superconductors.
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The establishment of third-generation synchrotron light sources at Lawrence Berkeley National Laboratory and at Argonne National Laboratory and the decision to construct the new Spallation Neutron Source (SNS) have dominated the decade as far as large national facilities are concerned.
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From page 25... ...
In turn, this new understanding holds the promise of breakthroughs at a time when the limits of incremental progress are being tested in materials-based technologies ranging from integrated circuits and magnetic storage devices to the synthesis of advanced polymers to the performance of materials under extreme conditions. Perhaps the greatest impact will be felt at the interface between biology and physics, where the convergence of condensedmatter and materials physics and molecular biology is expected to drive important advances in the fundamental understanding of biological processes.
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From page 26... ...
At national synchrotron facilities biologists are attacking the structure of biological molecules, chemists are improving drug designs, and environmental scientists are following the migration of envi
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From page 27... ...
Recommendations for Major Materials Research Facilities · The insufficiency of neutron sources in the United States should be addressed in the short term by upgrading existing neutron-scattering facilities and in the long term by the construction of the Spallation Neutron Source. · Support for operations and upgrades at synchrotron facilities, including research and development on fourth-generation light sources, should be strengthened.
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From page 28... ...
The U.S. system of graduate education, research universities, government and industrial laboratories, and national facilities for condensed-matter and materials physics is a major reason for rapid progress in research and technological applications.
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· Universities should develop ways to bring the excitement and creativity of research and discovery into education at an earlier stage. · University departments should consider new professional degree programs that link undergraduate physics education with, for example, engineeringoriented disciplines.
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From page 30... ...
This is a new era. Vast new arenas, ranging from subtle quantum phenomena, to macromolecular science, to the realm of complex materials, are increasingly accessible to fundamental study.
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