What makes a university physics lab tick? Sean Kelley grabs a mic and heads to a lab that's trying to build an early quantum computer out of atomic ions. Marko Cetina and Kai Hudek, two research scientists at the University of Maryland who run the lab, explain what it takes to keep things from burning down and muse about the future of quantum computers.
Researchers have found that a small stretch is enough to unleash the exotic electrical properties of a newly discovered topological insulator, unshackling a behavior previously locked away at cryogenic temperatures.
The compound, called samarium hexaboride, has been studied for decades. But recently it has enjoyed a surge of renewed interest as scientists first predicted and then discovered that it was a new type of topological insulator—a material that banishes electrical currents from its interior and forces them to travel along its periphery. That behavior only emerges at around 4 degrees above absolute zero, though, thwarting potential applications.
Now, experimentalists at the University of California, Irvine (UCI), working with JQI Fellow Victor Galitski and former JQI postdoctoral researcher Maxim Dzero (now at Kent State University), have found a way to activate samarium hexaboride's cryogenic behavior at much higher temperatures. By stretching small crystals of the metal by less than a percent, the team was able to spot the signature surface currents of a topological insulator at 240 K (minus 33 C)—nearly room temperature and, in any case, a far cry from 4 K. The currents even persisted once the strain was removed.
Their technique, which was recently reported in Nature Materials, uses piezoelectric elements that bend when they are fed with an electric current. By suspending a sample of samarium hexaboride between two titanium supports and pulling on one side, researchers could measure the crystal's electrical properties for different temperatures and amounts of stretch.
Last year, Galitski partnered with the same experimental group at UCI and discovered a potential application for samarium hexaboride's unusual surface currents. They found that holding a small crystal at a fixed voltage could produce oscillating currents on its surface. Such tick-tock signals are at the heart of modern digital electronics, but they typically require clocks that are much larger than the micron-sized crystals.
The new result might make such applications more likely, and it could even be achieved without any piezo elements. It may be possible to grow samarium hexaboride as a thin film on top of another material that would naturally cause it to stretch, the researchers say.
REFERENCE PUBLICATION
"Surface-dominated conduction up to 240K in the Kondo insulator SmB6 under strain," A. Stern, M. Dzero, V.M. Galitski, Z. Fisk, J. Xia, Nature Materials, advance online publication, – (2017)
RESEARCH CONTACT
This email address is being protected from spambots. You need JavaScript enabled to view it.
MEDIA CONTACT
This email address is being protected from spambots. You need JavaScript enabled to view it.
RELATED JQI ARTICLES
Oscillating currents point to practical application for topological insulators
An Ideal Material
Topological Insulators
The Lorraine DeSalvo Chair's Endowed Award for Outstanding Service recognizes employees who provide benefit beyond their regular duties, promote positive professional and personal exchanges among colleagues, and work effectively within the Department of Physics and/or with outside contacts. Nominees must have been employed within the Department of Physics for a minimum of one year.
The Sibylle Sampson Award was established by Sibylle Sampson, a long-time Physics employee and valued assistant to former Chair John S. Toll. It spotlights an employee whose one-time accomplishment otherwise might go unrecognized. The employee’s undertaking will have benefited the entire Department or a specific unit, and shown creativity, initiative or self-motivation. Nominees must have been employed within the Department of Physics for a minimum of one year. Two nominators are needed for the Sibylle Sampson Award.
The Staff Excellence Award recognizes employees who excel in job performance, provide a friendly and supportive atmosphere, and display a personal commitment to the Department and to positive workplace morale. Up to three awards may be given. Nominees must have been employed within the Department of Physics for a minimum of one year.
| Year | DeSalvo Chair's Award | Sibylle Sampson Award | Staff Excellence Award |
|---|---|---|---|
| 2022 2021 2020 2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009
2007
2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995
1993
1991 1990
1988
1986
1984 1983 1982 | Clay Daetwyler Brian Straughn Jesse Anderson
Lorraine DeSalvo Bonnie Seal-Filiatreau Pauline Rirksopa Tommy Baldwin Mark Conners no awards Jane Zhang Paulina Alejandro Nicholas Hammer Jesse Anderson Clay Daetwyler
Robert Dahms Tom Payerle John Cataldi Mary Ridgell Joyce Robinson Margaret Lukomska Tom Payerle Pauline Rirksopa Lorraine DeSalvo Maurice Pairel Loretta Robinette Cassie Jones, Jesse Anderson Dawn Leavell Linda O'Hara, Betty Alexander Bernadine Kozlowski Geoffrey Elbo Pam Solomos, Nono Kusuma Jan Andrews Karl Harzer, Brenda Dunn Rose Otto Pota Floros, Harriet Husman Jean Clement Michele Eastman Elbert Barretta Delores Knight | Rob McIntire Naomi Russo Dannielle Watkins Samantha Suplee Ayla Hurley Paulina Alejandro Logan Anbinder Donna Hammer Allen Monroe no awards Anne Suplee Xiao Ning Zhao Pauline Rirksopa Bonnie Seal-Filiatreau Doug Bensen, Scott Lasley Loretta Robinette
Kari Aldridge Randy Holder Donna Hammer Sherri Menoes Margaret Lukomska Allen Monroe Al Godinez Tuck Owens Ruth Zerwitz Delores Knight Norman Reese
Pauline Rirksopa
| Josiland Chambers, Naomi Russo, Bonnie Seal-Filiatreau Lea Bartolome, Melanie Knouse, Allen Monroe Melissa Britton, Josiland Chambers, Tom Woycheck-Gleason, Ayla Hurley, Bonnie Seal-Filiatreau Janet Das Sarma, Donna Hammer, Kristin Stenson Heather Markle, Don Lynch, Jane Wang Jessica Crosby, Claudia Key and Kelly Phillips Margaret Lukomska, Naomi Russo and Melissa Britton Eliot Hammer Amy Streets no awards Julie Callis |
Christopher Monroe, Distinguished University Professor & Bice Seci-Zorn Professor was elected to the U.S. National Academy of Sciences 2016. See recorded video http://www.nasonline.org/NAS154presentation.
Membership of the National Academy of Sciences is one the greatest and highest honors that a scientist can receive. "The NAS membership totals approximately 2,290 members and 490 foreign associates, of whom approximately 200 have received Nobel prizes." - NAS
Read more about Monroe's accomplishments.