https://phys.org/news/2023-06-physicists-superconductivity.html Phys.org Topics * Week's top * Latest news * Unread news * Subscribe [ ] Science X Account [ ] [ ] [*] Remember me Sign In Click here to sign in with or Forget Password? Not a member? Sign up Learn more * Nanotechnology * Physics * Earth * Astronomy & Space * Chemistry * Biology * Other Sciences * Medical Xpress Medicine * Tech Xplore Technology [INS::INS] * * share this! * 535 * 81 * Share * Email 1. Home 2. Physics 3. Superconductivity * * * --------------------------------------------------------------------- June 22, 2023 Editors' notes This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: fact-checked peer-reviewed publication trusted source proofread Physicists discover a new switch for superconductivity by Jennifer Chu, Massachusetts Institute of Technology superconductivity Credit: CC0 Public Domain Under certain conditions--usually exceedingly cold ones--some materials shift their structure to unlock new, superconducting behavior. This structural shift is known as a "nematic transition," and physicists suspect that it offers a new way to drive materials into a superconducting state where electrons can flow entirely friction-free. But what exactly drives this transition in the first place? The answer could help scientists improve existing superconductors and discover new ones. Now, MIT physicists have identified the key to how one class of superconductors undergoes a nematic transition, and it's in surprising contrast to what many scientists had assumed. The physicists made their discovery studying iron selenide (FeSe), a two-dimensional material that is the highest-temperature iron-based superconductor. The material is known to switch to a superconducting state at temperatures as high as 70 kelvins (close to -300 degrees Fahrenheit). Though still ultracold, this transition temperature is higher than that of most superconducting materials. The higher the temperature at which a material can exhibit superconductivity, the more promising it can be for use in the real world, such as for realizing powerful electromagnets for more precise and lightweight MRI machines or high-speed, magnetically levitating trains. For those and other possibilities, scientists will first need to understand what drives a nematic switch in high-temperature superconductors like iron selenide. In other iron-based superconducting materials, scientists have observed that this switch occurs when individual atoms suddenly shift their magnetic spin toward one coordinated, preferred magnetic direction. But the MIT team found that iron selenide shifts through an entirely new mechanism. Rather than undergoing a coordinated shift in spins, atoms in iron selenide undergo a collective shift in their orbital energy. It's a fine distinction, but one that opens a new door to discovering unconventional superconductors. "Our study reshuffles things a bit when it comes to the consensus that was created about what drives nematicity," says Riccardo Comin, the Class of 1947 Career Development Associate Professor of Physics at MIT. "There are many pathways to get to unconventional superconductivity. This offers an additional avenue to realize superconducting states." Comin and his colleagues published their results in a study appearing in Nature Materials. Co-authors at MIT include Connor Occhialini, Shua Sanchez, and Qian Song, along with Gilberto Fabbris, Yongseong Choi, Jong-Woo Kim, and Philip Ryan at Argonne National Laboratory. [INS::INS] Following the thread The word "nematicity" stems from the Greek word "nema," meaning "thread"--for instance, to describe the thread-like body of the nematode worm. Nematicity is also used to describe conceptual threads, such as coordinated physical phenomena. For instance, in the study of liquid crystals, nematic behavior can be observed when molecules assemble in coordinated lines. In recent years, physicists have used nematicity to describe a coordinated shift that drives a material into a superconducting state. Strong interactions between electrons cause the material as a whole to stretch infinitesimally, like microscopic taffy, in one particular direction that allows electrons to flow freely in that direction. The big question has been what kind of interaction causes the stretching. In some iron-based materials, this stretching seems to be driven by atoms that spontaneously shift their magnetic spins to point in the same direction. Scientists have therefore assumed that most iron-based superconductors make the same, spin-driven transition. But iron selenide seems to buck this trend. The material, which happens to transition into a superconducting state at the highest temperature of any iron-based material, also seems to lack any coordinated magnetic behavior. "Iron selenide has the least clear story of all these materials," says Sanchez, who is an MIT postdoc and NSF MPS-Ascend Fellow. "In this case, there's no magnetic order. So, understanding the origin of nematicity requires looking very carefully at how the electrons arrange themselves around the iron atoms, and what happens as those atoms stretch apart." A super continuum In their new study, the researchers worked with ultrathin, millimeter-long samples of iron selenide, which they glued to a thin strip of titanium. They mimicked the structural stretching that occurs during a nematic transition by physically stretching the titanium strip, which in turn stretched the iron selenide samples. As they stretched the samples by a fraction of a micron at a time, they looked for any properties that shifted in a coordinated fashion. Using ultrabright X-rays, the team tracked how the atoms in each sample were moving, as well as how each atom's electrons were behaving. After a certain point, they observed a definite, coordinated shift in the atoms' orbitals. Atomic orbitals are essentially energy levels that an atom's electrons can occupy. In iron selenide, electrons can occupy one of two orbital states around an iron atom. Normally, the choice of which state to occupy is random. But the team found that as they stretched the iron selenide, its electrons began to overwhelmingly prefer one orbital state over the other. This signaled a clear, coordinated shift, along with a new mechanism of nematicity, and superconductivity. "What we've shown is that there are different underlying physics when it comes to spin versus orbital nematicity, and there's going to be a continuum of materials that go between the two," says Occhialini, an MIT graduate student. "Understanding where you are on that landscape will be important in looking for new superconductors." More information: Occhialini, C.A., et al, Spontaneous orbital polarization in the nematic phase of FeSe, Nature Materials (2023). DOI: 10.1038/s41563-023-01585-2. www.nature.com/articles/ s41563-023-01585-2 Journal information: Nature Materials Provided by Massachusetts Institute of Technology This story is republished courtesy of MIT News (web.mit.edu/ newsoffice/), a popular site that covers news about MIT research, innovation and teaching. Citation: Physicists discover a new switch for superconductivity (2023, June 22) retrieved 26 June 2023 from https://phys.org/news/ 2023-06-physicists-superconductivity.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. --------------------------------------------------------------------- Explore further Nematic transition and nanoscale suppression of superconductivity in an iron chalcogenide --------------------------------------------------------------------- 620 shares * Facebook * Twitter * Email Feedback to editors [INS::INS] * Featured * Last Comments * Popular Cochlea cell atlas built from single-cell sequencing discovers new cell types, uncovers hidden molecular features 9 hours ago 0 New millisecond pulsar detected with FAST 9 hours ago 0 Remote lake emissions from the Tibetan Plateau challenge global climate modeling 9 hours ago 2 Microsoft claims to have achieved first milestone in creating a reliable and practical quantum computer Jun 24, 2023 4 White dwarf's strong magnetic field fooled scientists into thinking it would pass close to our solar system, study shows Jun 23, 2023 0 --------------------------------------------------------------------- [gif] Hidden in plain sight: Rare palm species that flowers underground discovered in Borneo 1 minute ago [gif] Study reveals reason hellbenders are disappearing 1 hour ago [gif] Some black truffles grown in eastern US may be less valuable lookalike species, study finds 1 hour ago [gif] Researchers estimate that gray whales off Oregon Coast consume millions of microparticles per day 2 hours ago [gif] Dolphin moms use baby talk to call to their young, recordings show 3 hours ago [gif] Investigating the intricacies of auxin signaling mechanisms in algae 3 hours ago [gif] Research shows more than 90% of global aquaculture faces substantial risk from environmental change 3 hours ago [gif] Ninth Dedekind number discovered: Scientists solve long-known problem in mathematics 3 hours ago [gif] Study finds human impact on wildlife even in protected areas 3 hours ago [gif] New study finds investing in nature improves equity, boosts economy 4 hours ago [INS::INS] * Related Stories [gif] Nematic transition and nanoscale suppression of superconductivity in an iron chalcogenide Jun 16, 2021 [gif] Electronic map reveals 'rules of the road' in superconductor Dec 6, 2019 [gif] Iron selenide revealed as 'garden-variety iron-based superconductor' May 20, 2019 [gif] Spin keeps electrons in line in iron-based superconductor May 19, 2022 [gif] Physicists show quantum materials can be tuned for superconductivity Jan 17, 2019 [gif] Physicists uncover secrets of world's thinnest superconductor May 27, 2021 * Recommended for you [gif] Novel 'toggle-switch' could lead to more versatile quantum processors with clearer outputs 4 hours ago [gif] New method to find Majorana particles tested for the first time Jun 22, 2023 [gif] New cooling technology developed for quantum computing circuits Jun 16, 2023 [gif] New superconducting diode could improve performance of quantum computers and artificial intelligence Jun 6, 2023 [gif] Tiny quantum electronic vortexes can circulate in superconductors in ways not seen before Jun 1, 2023 [gif] Scientists find first evidence for new superconducting state in Ising superconductor May 24, 2023 Load comments (0) Let us know if there is a problem with our content Use this form if you have come across a typo, inaccuracy or would like to send an edit request for the content on this page. For general inquiries, please use our contact form. For general feedback, use the public comments section below (please adhere to guidelines). Please select the most appropriate category to facilitate processing of your request [-- please select one -- ] [ ] [ ] [ ] [ ] [ ] Your message to the editors [ ] Your email (only if you want to be contacted back) [ ] Send Feedback Thank you for taking time to provide your feedback to the editors. Your feedback is important to us. However, we do not guarantee individual replies due to the high volume of messages. E-mail the story Physicists discover a new switch for superconductivity Your friend's email [ ] Your email [ ] [ ] I would like to subscribe to Science X Newsletter. Learn more Your name [ ] Note Your email address is used only to let the recipient know who sent the email. Neither your address nor the recipient's address will be used for any other purpose. The information you enter will appear in your e-mail message and is not retained by Phys.org in any form. [ ] [ ] [ ] [ ] [ ] [ ] [ ] Your message [ ] Send Newsletter sign up Get weekly and/or daily updates delivered to your inbox. You can unsubscribe at any time and we'll never share your details to third parties. [ ] Subscribe More information Privacy policy Donate and enjoy an ad-free experience We keep our content available to everyone. Consider supporting Science X's mission by getting a premium account. Remove ads Maybe later Medical Xpress Medical Xpress Medical research advances and health news Tech Xplore Tech Xplore The latest engineering, electronics and technology advances Science X Science X The most comprehensive sci-tech news coverage on the web Newsletters [ ] Subscribe Science X Daily and the Weekly Email Newsletter are free features that allow you to receive your favorite sci-tech news updates in your email inbox Follow us * * * * * Top * Home * Search * Mobile version * Help * FAQ * About * Contact * Science X Account * Premium Account * Archive * News wire * Android app * iOS app * RSS feeds * Push notification (c) Phys.org 2003 - 2023 powered by Science X Network Privacy policy Terms of use Your Privacy This site uses cookies to assist with navigation, analyse your use of our services, collect data for ads personalisation and provide content from third parties. By using our site, you acknowledge that you have read and understand our Privacy Policy and Terms of Use. Ok Cookie options E-mail newsletter [ ] Subscribe Follow us * * * * It appears that you are currently using Ad Blocking software. What are the consequences? x Quantcast