Researchers Solve Mystery about Arrangement of Atoms in Metal Using Extreme Pressure

A decades-old puzzle about a widely used metal has been solved by Researchers using very high pressure experiments and powerful supercomputing.

Their discovery reveals crucial core aspects of the element lithium, the simplest and lightest metal in the periodic table. The material is typically used in batteries for computers and phones.

Atom arrangement

A mystery of how the atoms in a metal are arranged – which impacts properties such as its malleability, strength and conductivity – has been solved by their study.

An international team aimed to better comprehend lithium’s structure by examining it at cold temperatures. In this low-energy state, the important properties of materials can be clearly observed.

Complex calculations

So far, it was hard for Researchers to explain earlier experimental results specifying that lithium had a complex structure. To understand the theory correctly required remarkably accurate calculations using latest quantum mechanics.

Simple structure

Their recent calculations, using the ARCHER supercomputer at the University of Edinburgh, revealed that lithium’s structure is not complex or disordered, as earlier results had proposed. In reality, its atoms are arranged orderly, like oranges in a box.

High pressures

Researchers explain that in earlier experiments, fast cooling resulted in misleading results. To avoid those issues, they attained low-temperature conditions by placing samples of lithium under very high pressure – up to 4,500 times that of Earth’s atmosphere – by squeezing it between two diamonds. They then cooled and depressurized the sample before studying it using a synchotron device, which applied X-ray beams to see atoms.

The research, from the Universities of Edinburgh and Utah, has been published in Science.   

Our calculations needed an accuracy of one in 10 million, and would have taken over 40 years on a normal computer.

Dr Miguel Martinez-Canales, the University of Edinburgh's School of Physics and Astronomy

Professor Graeme Ackland, of the University of Edinburgh's School of Physics and Astronomy, said, "We were able to form a true picture of cold lithium by making it using high pressures. Rather than forming a complex structure, it has the simplest arrangement that there can be in nature."

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