Chemist Jeffrey Long is daring to remake the ubiquitous computer hard drive. Long is devising ways in which chemists can assemble large inorganic molecules packed with different metals to create a host of novel materials for use in the emerging field of nanotechnology. His first target is the molecular magnet, a chemical structure whose electrons can be set spinning in synchrony by a magnetic field. Molecular magnets are a potential replacement for the increasingly crowded metallic films that constitute computer hard drives. Each molecular magnet could represent one bit of memory, enabling storage densities a thousand times greater than those of the best existing films. Long began building his own molecular magnets in 1997, demonstrating a scheme for packing them with progressively more chromium, cobalt and nickel. Unfortunately, his best clusters can only be magnetized at a chilly -270 °C, just 3 °C above absolute zero. Making more practical molecular magnets may take years, but if this field heats up, it could revolutionize computer storage.
Ten years ago,Adekunle Adeyeye left his computer-programming job in Ibadan,Nigeria, to get a master’s in microelectronics engineering at the University of Cambridge in England.Despite a rocky start,he finished atop his class.He joined the physics PhD program at the university’s Cavendish Laboratory,where he researched magnetism in thin films.He then became the first Nigerian elected as a prestigious junior research fellow of Trinity College at Cambridge.There,Adeyeye devised nanofabrication tech- niques that allowed him to create novel nano magnets.His mentor,physicist Stephen Julian, attributes Adeyeye’s success to “tremendous energy and creativity.”Today Adeyeye is a founding researcher at the $10 million Information Storage Materials Laboratory at the National University of Singapore,where he works in the field of “spintronics.”Conventional electronics take advan- tage of the charge of electrons in semiconducting materials.But electrons also have a property called “spin.”If Adeyeye succeeds in better utilizing electron spin,he could help revolutionize memory and logic devices,leading to smaller,faster and less power-hungry computers.
When he was 10, Doug Barlage started making electronic toys with store-bought transistors. Now at Intel, he is building the world’s smallest, fastest transistors for future computers. In particular, he has improved the devices’ gate oxide—a thin layer that prevents transistors from leaking current but limits their size and speed. Intel’s latest version is just three atoms thick. Until Barlage came along, researchers struggled with how to determine he electrical properties of materials so thin; some thought it pointless. Barlage forged ahead, getting more performance from advanced measuring tools than their manufacturers thought possible. “We drove right through the stop sign, ”he says.The results allowed Barlage to build the optimal gate- oxide configurations. Using designs made possible by Barlage’s measurements, Intel has twice set the world record for transistor size and speed, and a third record is close at hand. Coworkers describe Barlage as “meticulous and driven ”as he explores just how far he can push transistor technology
Angela Belcher “fell in love” with molecules as a college freshman. As a doctoral student at the University of California, Santa Barbara, she answered provocative questions that fused the biological and physical sciences. Chief among them: could proteins sculpt the structure of semiconductors? Belcher identified a series of proteins that bind to semiconducting nanoparticles and used them to help direct the assembly of the nanoparticles in ways not possible before. Belcher and her postdoctoral advisor, Evelyn Hu, formed a company, Semzyme, based in Santa Barbara, CA,to create such protein tools. Now at the University of Texas, Belcher says her passion for science remains so intense that she often wakes at 2:00 a.m. ready to head to the lab. Recently, her team discovered a novel way to make liquid crystalline films. Belcher is also using proteins loaded with semiconductors to help create nanoscale “quantum wires”for tiny electronic components. Belcher plans to continue her research this fall as an MIT professor.
Unchallenged by high-school physics labs, Mariangela Lisanti went looking for a “real” project the summer after her junior year. She approached nanotechnology expert Mark Reed at Yale University. His challenge: design a better way to measure the conductance of a single atom in a nanowire. With virtually no help, Lisanti taught herself quantum mechanics, built an apparatus at Yale and generated data. Reed was floored: “In two months she did what often takes postdocs one or two years—with significantly less supervision.” After her senior year, Lisanti improved her apparatus so it generated more data in a day than other approaches did in three months. She spent $35 on parts; other setups cost $100,000.Reed says Lisanti also unveiled aspects of conductance “never observed before.” Researchers nationwide have asked to use her technique. The first student to place first in the Intel Science Talent Search and the Siemens Westinghouse Science and Technology Competition, Lisanti is now a freshman at Harvard University. “My passion,” she says with a joyous smile, “is to explain things that haven’t been explained.”
One of the first things you notice about Scott Manalis’s CV is a substantial list of patents. A tour of his orderly but jam-packed lab, replete with an ultrasensitive microaccelerometer and microelectromechanical devices, confirms that Manalis likes to build gadgets that work on the scale of nanometers and micrometers. Trained in applied physics,and an expert on the equipment used to image and manipulate atoms, he hopes to create revolutionary new tools for advancing molecular biology. He wants to get direct information on DNA or protein molecules by binding them to, say, silicon transistors or tiny cantilevers. His dream, he says, is that within five to 15 years, he’ll be able to “stick a probe into a cell, connect it to a computer” and get real-time information on the cell’s proteins and genes. Such a tool would be invaluable to molecular biologists, replacing weeks or months of laboratory analysis. It may take a while, but Manalis is already creating the technology to make his dream reality.
Jan Hendrik Schön
Hendrik Schön is reinventing the transistor at the place it was born. He and his Bell Labs coworkers have produced single-molecule transistors whose electrical performance is comparable to that of today’s best silicon devices but which are hundreds of times smaller. Making such molecular transistors, which could lead to ultrafast, ultrasmall computers, has been a goal of researchers for years; Schön’s clever design established Bell Labs as a leader in the race. But Schön is not interested in simply reinventing the transistor. He wants to change the very materials that form microelectronics,replacing inorganic semiconductors with organic molecules. Schön has made an organic high-temperature superconductor, renewing hopes that superconductors could have widespread electronic applications. He also helped devise the first electrically driven organic laser, which could mean cheaper optoelectronic devices. The soft-spoken Schön recalls being “very surprised” by how well his molecular transistors worked. But it won’t be a surprise if Schön helps transform microelectronics.
Expect big things from Keith Schwab. Just don’t expect to hear much about them. Schwab has advanced quantum physics with two seminal discoveries: At the University of California, Berkeley, he devised ways to exploit the quirky quantum behavior of a frictionless fluid called superfluid, which could lead to a superaccurate gyroscope, important for space navigation and to measure minute changes in the earth’s rotation. Then, at Caltech, he became the first to measure the fundamental unit of heat flow, a constant that will limit nanoscale devices. That discovery was the subject of filmmaker Toni Sherwood’s 2000 documentary The Uncertainty Principle, popular at film festivals. Schwab lowered his profile when he joined the tight-lipped National Security Agency’s quantum computing initiative in College Park, MD. Its goal: a quantum computer, which could have unparalleled code-breaking power. Schwab is also building nanoscale machines to demonstrate another of physics ’bizarre properties: superposition, a particle’s ability to exist in two places at once. Schwab’s work is unclassified—for now.
Jun Ye is a laser Jedi, wielding beams so precise they are destined to become a nanotech force. The Shanghai-born physicist came to the United States for grad school in 1989,yearning for theoretical work. But the laser lab lured him, and he set about tightening the precision of its instruments—to brilliant effect. By 2001,Ye had produced a stream of photons with timing steadier than the oscillations of an atomic clock. Last year, he synchronized and phase-tracked two pulsating beams of different colors so closely that they melded into one coherent beam—a feat physicists had thought impossible. Ye’s phase-locked pulses can be shaped and shortened when different lasers are added to the mix. University of Colorado physicist Carl Wieman, whose atom-trapping laser tricks earned him a Nobel Prize last year, says Ye’s tunability gives nanotechnologists a new tool for simultaneously tweaking each bond in intricate molecules. Ye is now refining his tools to push the frontiers of a variety of fields. With pulses fast enough, Ye figures he can talk to an atom’s electrons.