Superconductivity is Heating Up

Superhydrides approach room temperature superconductivity at high pressure, George Washington University researchers report.


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    Credit: Russell Hemley/GWU

    Near room temperature superconductivity in superhydrides at megabar pressures

Newswise — WASHINGTON, DC, March 4, 2019 -- There are 5.5 million miles of power lines in this country -- each one is losing energy right now. This ongoing 2 to 4 percent overhead loss could be reduced or eliminated if a lower resistance transmitter could be found. Many zero resistance materials have been demonstrated in the lab since superconductivity was discovered in 1911. Unfortunately, these superconductors require low temperatures. Progress toward commercially viable superconductors that operate at or near ambient temperatures is a dream of physics, materials science and energy technology. 

Superhydrides were predicted by scientists at George Washington University to exhibit superconductivity at temperatures approaching room temperature in 2017. Now these scientists have confirmed their prediction in the laboratory in this new class of materials. Their results could be an important step in the pursuit of electric transmission without resistance losses. 

This week at the 2019 American Physical Society March Meeting in Boston, Russell Hemley will present the latest research on superconductivity in this class of materials. He will also participate in a press conference describing the work. Information for logging on to watch and ask questions remotely is included at the end of this news release. 

Theory predicts uncooled superconductivity in metallic hydrogen -- a condensed phase where H nuclei are crushed together in a delocalized band of their own valence electrons.  A conduction band lies energetically just above, so metallic hydrogen conducts. As such it behaves as an alkali metal -- but also as a very high temperature superconductor. The pressure required to make this still hypothetical material is estimated to be the scope of current experimental techniques. There have been unconfirmed reports of its observation. However, the results have not been reproduced. 

A related avenue in the pursuit of normal temperature superconductors focuses on hydrogen-rich materials that might mimic metallic hydrogen. Metal superhydrides (MHx x>6) appeared promising, according to the predictions of the George Washington University group. These materials are packed with hydrogen atoms in a configuration similar to their structure in metallic hydrogen. The George Washington University team synthesized one of these materials last year -- lanthanum superhydride -- and in recent experiments found the material is in fact a superconductor.  

They used a diamond anvil cell to create LaH10 specimens under pressures approaching 2 million atmospheres. The sample's electrical resistance plummeted; superconductivity continued almost to room temperature. These measurements were in good agreement with their theoretical prediction. 

Progress toward higher temperature superconductors will continue in this laboratory. Advances in understanding uncooled superconductivity will suggest new directions toward unpressurized approaches.

"The findings should open a new chapter in research on superconductivity," Hemley said. "The work also shows the importance of ‘materials by design’ in the creation of new materials." 

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The 2019 APS March Meeting presentation “Near room temperature superconductivity in superhydrides at megabar pressures," by Russell Hemley, will take place Monday, March 4, at 11:15 a.m. in room 156A of the Boston Convention and Exhibition Center. ABSTRACT: http://meetings.aps.org/Meeting/MAR19/Session/B17.1 

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----------------------- MORE MEETING INFORMATION ----------------------- 

The American Physical Society (APS) March Meeting is a major international conference and the largest physics meeting of the year. In 2019, the APS March Meeting will convene March 4-8 at the Boston Convention and Exhibition Center. 

USEFUL LINKS 

Register as Press: https://goo.gl/forms/ur9dE24zCO1IVsLu2 
Press Site: https://www.aps.org/meetings/march/press.cfm 
Meeting Abstracts: http://meetings.aps.org/Meeting/MAR19/APS_epitome 
Main Meeting Page: https://www.aps.org/meetings/march/ 
Hotel and Travel: https://www.aps.org/meetings/march/hotel-travel.cfm 

PRESS REGISTRATION 

APS will provide free registration to all staff journalists representing media organizations, professional freelance journalists on assignment, and student journalists who are attending the meeting for the express purpose of gathering and reporting news and information. Press registration grants full access to all scientific sessions, to the press room, and to the press conferences. We will also provide complimentary press registration to university press officers, PIOs and other professional media relations staff. For press related questions about the APS March Meeting, email media@aps.org

PRESS CONFERENCES 

A series of press conferences on newsworthy research will be webcast live from the conference on Monday, March 4 through Thursday, March 7. A schedule will be released the week before the conference. Members of the media should register in advance at https://webcast.apswebcasting.com/go/aps-march-19

ABOUT APS 

The American Physical Society is a nonprofit membership organization working to advance and diffuse the knowledge of physics through its outstanding research journals, scientific meetings, and education, outreach, advocacy, and international activities. APS represents over 55,000 members, including physicists in academia, national laboratories, and industry in the United States and throughout the world. Society offices are located in College Park, Maryland (Headquarters), Ridge, New York, and Washington, D.C. Read more: https://www.aps.org/ 

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