California NanoSystems Institute
CNSI
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June 07, 2005

David Awschalom
UC Santa Barbara


Streaming Video
  

Spintronics: Semiconductors, Molecules, and Quantum Information Processing
Abstract:

There is a growing interest in exploiting electronic and nuclear spins in semiconductor nanostructures for the manipulation and storage of information in emergent technologies based upon spintronics and quantum logic. Such schemes offer qualitatively new scientific and technological opportunities by combining elements of standard electronics with spin-dependent interactions between electrons, nuclei, electric and magnetic fields. Here we provide an overview of recent developments in the field through a discussion of temporally- and spatially-resolved magneto-optical measurements, initially designed for probing local moment dynamics in magnetically doped semiconductor nanostructures. We demonstrate new electrical schemes for the local generation and manipulation of spins in conventional semiconductor heterostructures, thereby providing a compelling proof-of-concept that quantum spin information can be controlled within high-speed electrical circuits. Furthermore, we discuss a different experimental approach that enables the molecular wiring and assembly of colloidal semiconductor nanostructures to engineer hybrid systems for room temperature coherent spin transport. These experiments explore electronic, photonic, and magnetic control of spin in a variety of nanostructures, and show significant steps towards spin-based quantum information processing in the solid state.

References:

D. D. Awschalom, M. E. Flatt © and N. Samarth, "Spintronics," (Cover article), Scientific American 286, 66 (June 2002).

M. Ouyang and D. D. Awschalom, "Coherent Spin Transfer Between Molecularly Bridged Quantum Dots," Science 301, 1074 (2003).

Y. K. Kato, R. C. Myers, A. C. Gossard, and D. D. Awschalom, "Observation of the Spin Hall Effect in Semiconductors," (Cover article), Science 306, 1910 (2004).

May 31, 2005

Reshef Tenna
Department of Materials and Interfaces, Weizmann Institute, Israel
Inorganic Nanotubes and Inorganic Fullerene - Like Materials From Layered Compounds: Concept to Applications
Abstract:

We have proposed in 1992(1) that nanoparticles of layered compounds, like MoS2 and WS2 will be unstable against folding and close into fullerene-like structures and nanotubes (IF). Nanotubes and fullerene-like structures were prepared from numerous compounds with layered and recently also non-layered structure by various groups. The progress in the synthesis of inorganic nanotubes and fullerene-like nanoparticles will be reviewed. Substantial progress has been accomplished in the study of such nanoparticles for tribological applications(2) and more recently as reinforcing elements in nanocomposites, catalysis, rechargeable batteries, solar cells, etc. Efforts to scale-up the production of IF-WS2 to the level of a few tons/day by "ApNano Materials" are underway.

References:

1. R. Tenne et al., Nature 60, 444 (1992); b. Y. Feldman et al., Science 267, 222 (1995).

2. L. Rapoport et al., Nature 1997, 387, 791; b. L. Rapoport, N. Fleischer and R. Tenne, J. Mater. Chem., 15, 1782 (2005).

May 24, 2005

Dean Astumian
University of Maine


Streaming Video
  

Controlling Motion at the Nanoscale: How to Swim in Molasses and Walk in a Hurricane
Abstract:

Recently chemists have synthesized molecules that emulate in part the remarkable capabilities of bio-molecular motors. Like their biological counterparts, these synthetic machines function in an environment where viscous forces dominate inertia - they must "swim in molasses". Further, the power exchanged reversibly between the motor and its environment is many orders of magnitude greater than the power provided by the chemical fuel or external energy to drive directed motion. One might think that moving in a specific direction would be a difficult as walking in a hurricane. Yet these motors move and accomplish their function with almost deterministic precision. I will discuss the design principles by which synthetic molecules can function as "Brownian motors" by taking advantage of the ubiquitous thermal noise in their viscous environment.

Articles (pdf files)

:: Making Molecules into Motors
:: Brownian Motors
:: Thermodynamics and Kinetics of a Brownian Motors

May 17, 2005

Mark Thompson
USC


Streaming Video
  

Efficient Light Emission from Nanoscale Devices
Abstract:

There has been a great deal of interest in developing new materials for the fabrication of light emitting diodes, built from molecular and polymeric materials. These devices are built of multiple organic films, each typically 20-40 nm in thickness, sandwiched between planar anodes and cathodes. Our work has focused on understanding the limitations of the materials in hand and designing both new material and device architectures that have led to efficiencies approaching 100%. I will discuss the materials and device structures we developed to achieve these high efficiencies. We have taken particular advantage of dopant aggregation for Pt complexes to both tune color and device properties. Aggregates ranging from dimers to small aggregates are selectively formed and are responsible for a significant fraction of the emitted light.

References:

Biwu Ma, Jian Li, Peter I. Djurovich, Muhammed Yousufuddin, Robert Bau, and Mark E. Thompson; Synthetic Control of Pt***Pt Separation and Photophysics of Binuclear Platinum Complexes; J. AM. CHEM. SOC. vol. 127, No. 1, 2005 p.127,28,29.

May 10, 2005

Ahmed Busnaina
Northeastern University


Streaming Video
  

Nanomanufacturing Using Nanotemplates for Directed Assembly of Nanoelements
Abstract:

The electronics industry is looking for new nanoscale technologies that will be energy efficient with high performance, scalable with gain and operational reliability at room temperature that are preferably compatible with CMOS process and architecture. Proposed nanoelectronic devices using technologies beyond currently-deployed are many; mechanical or molecular switches, spin logic, phase logic, molecular devices, cross-bar devices, cross-net devices, etc. Manufacturing of these involves very diverse fabrication and assembly techniques that may involve top-down, bottom or both. There is a need to develop heterogeneous process integration such as combination of hierarchical directed assembly techniques with other processing techniques. High-throughput hierarchical directed assembly and nanoscale components and interconnect reliability will also be essential in going beyond silicon. Another important nanomanufacturing issue is nanoscale defect mitigation and removal and defect tolerant materials, structures and processes in addition to nanoscale metrology tools, such as in-line or in-situ monitoring and feedback. Fundamental understanding and novel technology in high rate, high volume integration and assembly of robust tools and processes are addressed. Nanotemplates and tools are used to accelerate the creation of highly anticipated commercial products and will enable the creation of an entirely new generation of applications. This requires understanding what is essential for a rapid multi-step, high volume/high rate processes, as well as for accelerated-life testing of nanoelements and defect-tolerance.

May 03, 2005

Jim Wells
Sunesis Pharmaceuticals


Streaming Video
  

Regulating Nano-Biology with Small Molecules
Abstract:

Enzymes are the nano-machines of life. Discovering how they are regulated provides clues to how they integrate with other signalling pathways, and how we may manipulate them for drug discovery. Using a site-directed discovery approach called Tethering we can selectively probe regions of these nano machines. This allows one to discover functional hot-spots and the mechanical gears and levers that control enzyme activity.

References:

Erlanson, D.A., Wells, J.A. and Braisted, A.B. (2004) Annu. Rev. Biophys. Biomol Struct. "TETHERING: Fragment-based Drug Discovery". 33, 199-233.

Hardy, J.A., Lam, J., Nguyen, J.T., O'Brien, T and Wells, J.A. (2004) Proc. Natl. Acad. Sci. USA "Discovery of an Allosteric Site in Caspases". 101, 12461-12466.

April 26, 2005

Omar Yaghi
University of Michigan


Streaming Video
  

Inorganic Genome and The Design of Nano Fuel Tanks
Abstract:

Inorganic and organic building blocks are used to construct crystalline nanoporous frameworks and discrete polyhedra. The basic principles for their design and assembly will be presented in the context of producing crystals with very high surface areas (5,000 m2/g) and large pore volumes leading to applications in gas storage.

References:

Reticular Chemistry: Occurrence and Taxonomy of Nets, and Grammar for the Design of Frameworks, N. Ockwig, O. D. Friedrichs, M. O'Keeffe, O. M. Yaghi, Acc. Chem. Res. 2005, 38, 176.

A Route to High Surface Area, Porosity and Inclusion of Large Molecules in Crystals, H. Chae, D. Y. Siberio-Perez, J. Kim, Y. Go, M. Eddaoudi, A. Matzger, M. O'Keeffe, O. M. Yaghi, Nature, 2004, 427, p. 523.

Metal-Organic Frameworks as New Materials for Hydrogen Storage, N. Rosi, M. Eddaoudi, D. Vodak, J. Eckert, M. O'Keeffe, O. M. Yaghi, Science, 2003, 300, p. 1127.

April 19, 2005

Eldon Emberly
Simon Fraser University, Canada


Streaming Video
  

Transcriptioneering: Some Thoughts on the Logic of Genes
Abstract:

All cells of an organism share the same genetic information (namely genes), yet clearly there is a great variety of cell types. The variety stems in part from how the genes are turned on or off within a cell. The cell in some sense 'computes' the output of its genes based on the input that it receives. In this talk I will present results from recent work that has coupled experimental and theoretical work to help elucidate the genetic program that underlies the early development of the fruit fly. I will then comment on how these findings might facilitate the design of future synthetic genetic circuitry.

References:

Schroeder MD, Pearce M, Fak J, Fan H, Unnerstall U, Emberly E, Rajewsky N, Siggia ED, Gaul U. PLoS Biol. 2004 Sep;2(9):E271.

April 12, 2005

Mark Pinto, CTO and Sr. Vice-President Applied Materials
Enabling the Nanoelectronics Era
Abstract:

For decades the scalability of MOS technology has fostered continual improvements in almost every dimension of electronic products. However at ~130nm, VLSI has neared a variety of limits threatening numerous compromises. In response the industry has returned to a state more like the 1970s where new directions in materials, processes and devices are being intensively evaluated. However the complexity of the challenge today is many orders of magnitude higher, e.g. controlling atomic thickness over billions of components, while the economic pressures, both on R&D expense as well as time to yield, are driving a new industry landscape. This presentation explores key technology challenges and reviews some of the main industry directions - many times across traditional R&D boundaries - that will enable the pervasive growth in semiconductor end application content promised by the nanoelectronics era.

References:

[1] M. Pinto, "Atoms to Applets: Building Systems ICs in the 21st Century", International Solid State Circuits Conference Technical Digest, Feb. 2000 (invited).

[2] J. Bude, A. Frommer, M. Pinto, G. Weber, "EEPROM/Flash sub 3.0V drain-source bias hot carrier writing", International Electron Devices Meeting Technical Digest, Dec 1995.

[3] M. Pinto, C. Rafferty, R. K. Smith, "ULSI Technology Development by Predictive Simulation,", International Electron Devices Meeting Technical Digest, Dec. 1993 (invited).

[4] R. Kazarinov, M. Pinto, "Carrier Transport in Laser Heterostructures," IEEE Journal of Quantum Electronics, Jan. 1994.

[5] S. Luryi, M. Pinto, "Broken Symmetry and the Formation of Hot-Electron Domains in Real-Space Transfer Transistors," Phys. Rev. Letters, Oct 1991.

[6] M. Pinto, R. Dutton, "Accurate Trigger Condition Analysis for CMOS Latch-up", IEEE Electron Device Letters, Feb. 1985.
April 05, 2005

Seth Putterman
UCLA
Energy Focusing at the NanoScale: Sonoluminescence and More
Abstract:

Fluids and solids that are driven off equilibrium do not return smoothly to the equilibrium state. Instead they can display a wide range of energy focusing phenomena. In sonoluminescence a sound wave passing through a fluid has its energy concentrated by 12 orders of magnitude to create ultraviolet picosecond flashes of light that originate from nanometer size hot spots whose temperature can reach a million degrees. At the very low frequencies achieved with a water hammer the strength of a single flash can be up-scaled by 6 orders of magnitude so as to be visible to this audience, in a real time demonstration. In a ferroelectric crystal such as Lithium Tantalate the application of heat leads to the expulsion of electrons with energies that can exceed 100KeV. Upon striking a target x-rays are emitted. A crucial question relates to whether there exist experimental configurations in which energy focusing processes can be used to generate nuclear fusion. Various medical applications employ energy focusing effects. Energy focusing also plays a role in turbulence, where intermittency leads to the formation of unexpected structures. Static electricity generated by friction is another striking example of an energy focusing effect. In the "barometer light" dragging glass through mercury at a speed of 1mm/sec leads to picosecond electrical discharges where the electrons are accelerated to over 1% the speed of light. Experiments indicate that this effect is related to phenomena encompassed by everyday friction.