Science, Technology, Astronomy

Physicists Create a Working Transistor From a Single Atom

Australian and American physicists have built a working transistor from a single phosphorus atom embedded in a silicon crystal.

The group of physicists, based at the University of New South Wales and Purdue University, said they had laid the groundwork for a futuristic quantum computer that might one day function in a nanoscale world and would be orders of magnitude smaller and quicker than today’s silicon-based machines.

In contrast to conventional computers that are based on transistors with distinct “on” and “off” or “1” and “0” states, quantum computers are built from devices called qubits that exploit the quirky properties of quantum mechanics. Unlike a transistor, a qubit can represent a multiplicity of values simultaneously.

That might make it possible to factor large numbers more quickly than with conventional machines — thereby undermining modern data-scrambling systems that are the basis of electronic commerce and data privacy. Quantum computers might also make it possible to simulate molecular structures with great speed, an advance that holds promise for designing new drugs and other kinds of materials.

“Their approach is extremely powerful,” said Andreas Heinrich, an I.B.M. physicist. “This is at least a 10-year effort to make very tiny electrical wires and combine them with the placement of a phosphorous atom exactly where they want them.”

He said the research was a significant step toward making a functioning quantum computing system. However, whether quantum computing will ever be harnessed for useful tasks remains uncertain, and the researchers also noted that their work demonstrated the fundamental limits that today’s computers would be able to shrink to.

“It shows that Moore’s Law can be scaled toward atomic scales in silicon,” said Gerhard Klimeck, professor of electrical and computer engineering at Purdue. Moore’s Law refers to technology improvements by the semiconductor industry that have doubled the number of transistors on a silicon chip roughly every 18 months for the past half century. That has led to accelerating increases in performance and declining prices. “The technologies for classical computing can survive to the atomic scale.”

Demonstrations of single-atom transistors date from 2002, but the researchers from Purdue and New South Wales said they had made advances on two fronts: in the precision with which they were able to place the Lilliputian switch; and in using for the first time industry-standard techniques to build the circuitry, making it possible to read and write information from the tiniest-conceivable switch.

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Source: scinerds