Electronic devices are always shrinking in size but it's hard to imagine anything beating what researchers at the University of New South Wales have created: a tiny wire that doesn't even use electrons to carry a current.

Known as a hole quantum wire, it exploits gaps – or holes - between electrons. The relationship between electrons and holes is like that between electrons and anti-electrons, or matter and anti-matter.

The holes can be thought of as real quantum particles that have an electrical charge and a spin. They exhibit remarkable quantum properties and could lead to a new world of super-fast, low-powered transistors and powerful quantum computers.

Associate Professor Alex Hamilton and Dr Adam Micolich, who lead the UNSW Quantum Electronic Devices group in Sydney, Australia, say the discovery that the holes can carry an electrical current puts the team at the front of its field in the quantum electronics revolution.

Quantum wires are microscopically small, in this case about 100 times narrower than a human hair. They are so narrow that electrons can only pass along them in single file.

Manufacturers are keenly interested in them because they hold the potential for new high-speed electronics applications, known as spintronics, where semiconductor devices have both electric and magnetic properties.

Electrons have both electric (charge) and magnetic (spin) properties but today's micro-chips use only the charge properties of electrons.

"To move ahead with spintronics, we need to be able to control the magnetic properties with electronics," says Professor Hamilton.

"Quantum holes also have spin, and this can be strongly affected by electric impulses. So semiconductors that use holes, rather than electrons, would be good for spintronics and quantum information technologies that use spin to store and process data." 

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