Bulletin of the American Physical Society
APS March Meeting 2020
Volume 65, Number 1
Monday–Friday, March 2–6, 2020; Denver, Colorado
Session B36: Room temperature superconductivity in superhydrides at extreme pressuresInvited
|
Hide Abstracts |
Sponsoring Units: DCOMP DCMP Chair: Renata Wentzcovitch, Columbia Univ Room: 601/603 |
Monday, March 2, 2020 11:15AM - 11:51AM |
B36.00001: Clathrate Superhydrides Under High Pressure: A Class of Extraordinarily Hot Conventional Superconductors Invited Speaker: Yanming Ma Room-T superconductivity has been a century long-held dream of mankind and a focus of intensive research. In an effort to search for Room-T superconductors, we proposed the first-ever sodalite-like clathrate superhydride CaH6 1 suffering at extreme pressures that shows a potential of high superconductivity and is not captured at ambient pressure. |
Monday, March 2, 2020 11:51AM - 12:27PM |
B36.00002: Road to Hot Hydride Superconductors Invited Speaker: Muhtar Ahart The realization of superconductivity in dense hydrides in the vicinity of room temperature dates back to predictions of very high Tc in atomic metallic hydrogen and subsequently in doped metallic hydrogen alloys and compounds. Density-functional based structure-search methods calculations combined with BCS-type models predicted a series of dense hydride high Tc superconductors (e.g., CaH6, H3S) at megabar pressures (>100 GPa), followed by the still higher Tc superhydrides (e.g., LaHx, YHx, with x > 6). Using a variety of x-ray diffraction and transport measurements, we confirmed our predictions of the stability of LaH10 and its Tc to 260 K near 200 GPa as well as superconductivity in other La-H phases, results that were subsequently confirmed independently. Additional studies have been carried out on high Tc hydrides of Se, Ca, Se-S, and other ternary systems. The results are consistent with conventional superconductivity, though the mechanism is likely affected by strong quantum effects in these systems. These efforts highlight the novel physics of metallic hydrogen-like materials, the success of ‘materials by design’ using high pressures, and the possibility of superconductivity well above room temperature as recently predicted. |
Monday, March 2, 2020 12:27PM - 1:03PM |
B36.00003: Progress in high-temperature conventional superconductivity Invited Speaker: Mikhail Eremets Room-temperature superconductivity is becoming realistic given progress in conventional superconductivity: the critical temperature Tc =203 K has been discovered in H3S under high pressures ~150 GPa[1]. Even higher, nearly room temperature superconductivity has been recently found in superhydride LaH10[2, 3] with Tc ~ 250 K, following the theoretical predictions[4-6]. In this hydride, lanthanum atom is located at the center of the cage of hydrogen H24 and acts as electron donor contributing to electron pairing, while the hydrogen atoms form weak covalent bonds with each other within the cage. This structure is different from that of H3S, in which each hydrogen atom is connected by a strong covalent bond to the two nearby sulfur atoms. |
Monday, March 2, 2020 1:03PM - 1:39PM |
B36.00004: Electronic Structure and Superconductivity in Binary and Ternary Hydrides Under Pressure Invited Speaker: Eva Zurek First principles calculations are employed to interrogate the electronic structure and bonding in two structures types that a priori crystal structure prediction methods have found for many compressed alkaline earth and rare earth metal binary hydrides: the I4/mmm symmetry tetrahydrides, and the Im-3m symmetry hexahydrides. We explore the relationship between their structure and electronic structure, as well as their propensity for superconductivity. Moreover, the XtalOpt evolutionary algorithm is used to predict the structures of novel stable and metastable ternary hydrides that could potentially be synthesized in high pressure experiments, and their superconducting critical temperatures are estimated. |
Monday, March 2, 2020 1:39PM - 2:15PM |
B36.00005: Superconductivity in Yttrium and Thorium Polyhydrides: a Route to Industrial Applications Invited Speaker: Dmitrii Semenok Recent blast growth in hydride superconductivity (SC) has resulted in the achievement of near-room critical temperatures (ThH10: 161 K [1], H3S: 203 K [2], YH6: 226 K [3a-b], LaH10: 250 K [4]) in centimeter-sized mini DACs. The logical final step in this sequence is achieving the room-temperature superconductivity. This progress would not be possible without the development of modern DFT methods and algorithms for crystal structure prediction (e.g. USPEX, CALYPSO, AIRSS). Thanks to these methods, the results of numerical simulations of new superconductors in La-H, Y-H, Th-H, Ce-H systems have been experimentally confirmed in recent years. This is probably the first such great success of computational material science in the field of high-TC SC. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700