Novel phase of matter discovered

A team of physicists has discovered an unusual form of matter -- not a conventional metal, insulator, or magnet, for example, but something entirely different, a study says.

This phase, characterised by an unusual ordering of electrons, offers possibilities for new electronic device functionalities, the study said.

"The discovery of this phase was completely unexpected and not based on any prior theoretical prediction," said lead researcher David Hsieh, assistant professor of physics at California Institute of Technology in the US.

According to the researchers, this new phase of matter could hold the solution to a long-standing mystery in condensed matter physics having to do with high-temperature superconductivity - the ability for some materials to conduct electricity without resistance, even at temperatures approaching -100 degrees Celsius.

"The whole field of electronic materials is driven by the discovery of new phases, which provide the playgrounds in which to search for new macroscopic physical properties," Hsieh noted.

The physicists made the discovery while testing a laser-based measurement technique that they recently developed to look for what is called multipolar order.

The specific compound that the researchers studied was strontium-iridium oxide (Sr2IrO4), a member of the class of synthetic compounds broadly known as iridates.

Over the past few years, there has been a lot of interest in Sr2IrO4 owing to certain features it shares with copper-oxide-based compounds, or cuprates.

Cuprates are the only family of materials known to exhibit superconductivity at high temperatures--exceeding 100 Kelvin (-173 degrees Celsius).

Structurally, iridates and cuprates are very similar. And like the cuprates, iridates are electrically insulating anti-ferromagnets that become increasingly metallic as electrons are added to or removed from them through a process called chemical doping.

The findings were detailed online in the journal Nature Physics.