Physi­cists cre­ate new class of 2D ar­ti­fi­cial ma­te­ri­als

Iran Daily - - Science & Technology -

In 1965, a renowned Prince­ton Univer­sity physi­cist the­o­rized that fer­ro­elec­tric met­als could con­duct elec­tric­ity de­spite not ex­ist­ing in na­ture.

For decades, sci­en­tists thought it would be im­pos­si­ble to prove the the­ory by Philip W. Anderson, who shared the 1977 No­bel Prize in physics, sci­ wrote.

It was like try­ing to blend fire and wa­ter, but a Rut­gers-led in­ter­na­tional team of sci­en­tists has ver­i­fied the the­ory and their find­ings are pub­lished in Na­ture Com­mu­ni­ca­tions.

Jak Chakhalian, a team leader of the study and Pro­fes­sor Claud Lovelace En­dowed Chair in Ex­per­i­men­tal Physics at Rut­gers Univer­sity-new Brunswick, said, “It’s ex­cit­ing. We created a new class of two-di­men­sional ar­ti­fi­cial ma­te­ri­als with fer­ro­elec­tric-like prop­er­ties at room tem­per­a­ture that don’t ex­ist in na­ture yet can con­duct elec­tric­ity.

“It’s an im­por­tant link be­tween a the­ory and an ex­per­i­ment.”

A cor­ner­stone of tech­nol­ogy, fer­ro­elec­tric ma­te­ri­als are used in elec­tron­ics such as cell phone and other an­ten­nas, com­puter stor­age, med­i­cal equip­ment, high pre­ci­sion motors, ul­tra-sen­si­tive sen­sors and sonar equip­ment.

Chakhalian said, “None of their ma­te­ri­als con­ducts elec­tric­ity and the Rut­gers-led find­ings po­ten­tially could spawn a new gen­er­a­tion of de­vices and ap­pli­ca­tions.

“Fer­ro­electrics are a very im­por­tant class of ma­te­ri­als tech­no­log­i­cally.

“They move, shrink and ex­pand when elec­tric­ity is ap­plied and that al­lows you to move things with ex­quis­ite pre­ci­sion. More­over, ev­ery modern cell phone has tens of com­po­nents with prop­er­ties sim­i­lar to fer­ro­elec­tric ma­te­rial.”

Like many physi­cists, Chakhalian rel­ished a chal­lenge and he could not find a law of physics that said fer­ro­elec­tric met­als could not be created.

Chakhalian said, “So his team, in­clud­ing study lead au­thor Yan­wei Cao, a for­mer doc­toral stu­dent who is now a pro­fes­sor at the Chi­nese Academy of Sciences, tapped Chakhalian’s sta­teof-the-art tools to cre­ate sheets of ma­te­ri­als only a few atoms thick. It’s like mak­ing sand­wiches.

“When a ma­te­rial be­comes fer­ro­elec­tric, its atoms shift per­ma­nently and we wanted to add me­tal­lic prop­er­ties to an ar­ti­fi­cial crys­tal that con­ducts elec­tric­ity.

“So we took two very thin lay­ers to cre­ate a two-di­men­sional metal at the in­ter­face and added a third layer with spe­cial prop­er­ties to shift the atoms in that me­tal­lic layer, cre­at­ing a fer­ro­elec­tric-like metal.

“The new struc­ture has sev­eral func­tion­al­i­ties built-in, and this is a big win-win.”

sci­ This image shows the po­si­tions of atoms in a fer­ro­elec­tric-like metal that con­tains bar­ium ti­tanate, stron­tium ti­tanate and lan­thanum ti­tanate.

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