Topological insulator is hot new discovery

Bismuth telluride. That’s the latest material to spark interest among the physicists in their search for exciting new things to do with electrons.

Bismuth telluride. That’s the latest material to spark interest among the physicists in their search for exciting new things to do with electrons. Recent investigations using high energy X-rays at Stanford have shown that the substance is a topological insulator – a class of material within which electrons can, under certain circumstances, move without resistance. That’s similar to superconductivity and ballistic conduction, although each has its own characteristics.

This behaviour happens when the quantum spin of each electron is aligned with its motion – the quantum spin Hall effect – which means, as far as I can make out, it becomes impossible for the electron to bounce back along its own path. And if it can’t bounce, it can’t meet with resistance, so on it flows. Although the mechanism can’t carry very high currents, it does open up a whole new area of electron behaviour that may work particularly well with spintronics.

And that could be a whole new world of low power, high density, super-performing devices. Maybe.

Importantly, this effect happens with bismuth telluride at room temperature. Most of the interesting spintronic physics we know about wimps out at around 180 kelvin or -90 celsius, which is generally speaking incompatible with laptops.

(Tellurium, by the way, is one of the rarest elements on earth and if you're exposed to even tiny amounts, it will make your breath smell of garlic.)

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