MSGID: 1:317/3 646ee471   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Scientists find evidence for new superconducting state in Ising   
   superconductor    
      
     Date:   
         May 24, 2023   
     Source:   
         University of Groningen   
     Summary:   
         In a ground-breaking experiment, scientists have discovered the   
         existence of a superconductive state that was first predicted   
         in 2017. This discovery could have significant applications,   
         particularly in the field of superconducting electronics.   
      
      
         Facebook Twitter Pinterest LinkedIN Email   
      
   ==========================================================================   
   FULL STORY   
   ==========================================================================   
   In a ground-breaking experiment, scientists from the University of   
   Groningen, together with colleagues from the Dutch universities of   
   Nijmegen and Twente and the Harbin Institute of Technology (China),   
   have discovered the existence of a superconductive state that was   
   first predicted in 2017. They present evidence for a special variant   
   of the FFLO superconductive state on 24 May in the journal Nature. This   
   discovery could have significant applications, particularly in the field   
   of superconducting electronics.   
      
   The lead author of the paper is Professor Justin Ye, who heads the Device   
   Physics of Complex Materials group at the University of Groningen. Ye and   
   his team have been working on the Ising superconducting state. This is   
   a special state that can resist magnetic fields that generally destroy   
   superconductivity, and that was described by the team in 2015. In 2019,   
   they created a device comprising a double layer of molybdenum disulfide   
   that could couple the Ising superconductivity states residing in the two   
   layers. Interestingly, the device created by Ye and his team makes it   
   possible to switch this protection on or off using an electric field,   
   resulting in a superconducting transistor.   
      
   Elusive The coupled Ising superconductor device sheds light on a   
   long-standing challenge in the field of superconductivity. In 1964,   
   four scientists (Fulde, Ferrell, Larkin, and Ovchinnikov) predicted a   
   special superconducting state that could exist under conditions of low   
   temperature and strong magnetic field, referred to as the FFLO state. In   
   standard superconductivity, electrons travel in opposite directions   
   as Cooper pairs. Since they travel at the same speed, these electrons   
   have a total kinetic momentum of zero. However, in the FFLO state, there   
   is a small speed difference between the electrons in the Cooper pairs,   
   which means that there is a net kinetic momentum.   
      
   'This state is very elusive and there are only a handful of articles   
   claiming its existence in normal superconductors,' says Ye. 'However,   
   none of these are conclusive.' To create the FFLO state in a conventional   
   superconductor, a strong magnetic field is needed. But the role played by   
   the magnetic field needs careful tweaking. Simply put, for two roles to   
   be played by the magnetic field, we need to use the Zeeman effect. This   
   separates electrons in Cooper pairs based on the direction of their spins   
   (a magnetic moment), but not on the orbital effect -- the other role   
   that normally destroys superconductivity. 'It is a delicate negotiation   
   between superconductivity and the external magnetic field,' explains Ye.   
      
   Fingerprint Ising superconductivity, which Ye and his collaborators   
   introduced and published in the journal Science in 2015, suppresses   
   the Zeeman effect. 'By filtering out the key ingredient that makes   
   conventional FFLO possible, we provided ample space for the magnetic   
   field to play its other role, namely the orbital effect,' says Ye.   
      
   'What we have demonstrated in our paper is a clear fingerprint of   
   the orbital effect-driven FFLO state in our Ising superconductor,'   
   explains Ye. 'This is an unconventional FFLO state, first described in   
   theory in 2017.' The FFLO state in conventional superconductors requires   
   extremely low temperatures and a very strong magnetic field, which makes   
   it difficult to create. However, in Ye's Ising superconductor, the state   
   is reached with a weaker magnetic field and at higher temperatures.   
      
   Transistors In fact, Ye first observed signs of an FFLO state in his   
   molybdenum disulfide superconducting device in 2019. 'At that time,   
   we could not prove this, because the samples were not good enough,'   
   says Ye. However, his PhD student Puhua Wan has since succeeded in   
   producing samples of the material that fulfilled all the requirements to   
   show that there is indeed a finite momentum in the Cooper pairs. 'The   
   actual experiments took half a year, but the analysis of the results   
   added another year,' says Ye. Wan is the first author of the Nature paper.   
      
   This new superconducting state needs further investigation. Ye: 'There   
   is a lot to learn about it. For example, how does the kinetic momentum   
   influence the physical parameters? Studying this state will provide new   
   insights into superconductivity. And this may enable us to control this   
   state in devices such as transistors. That is our next challenge.'   
       * RELATED_TOPICS   
             o Matter_&_Energy   
                   # Spintronics # Electronics # Medical_Technology #   
                   Graphene   
             o Computers_&_Math   
                   # Spintronics_Research # Encryption # Hacking #   
                   Mathematical_Modeling   
       * RELATED_TERMS   
             o Electrical_engineering o Quantum_entanglement o   
             Superconducting_Super_Collider o Schro"dinger's_cat   
             o Electricity o Breaking_wave o Tissue_engineering o   
             Materials_science   
      
   ==========================================================================   
   Story Source: Materials provided by University_of_Groningen. Note:   
   Content may be edited for style and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Puhua Wan, Oleksandr Zheliuk, Noah F. Q. Yuan, Xiaoli Peng,   
      Le Zhang,   
         Minpeng Liang, Uli Zeitler, Steffen Wiedmann, Nigel E. Hussey,   
         Thomas T.   
      
         M. Palstra, Jianting Ye. Orbital Fulde-Ferrell-Larkin-Ovchinnikov   
         state in an Ising superconductor. Nature, 2023; DOI:   
         10.1038/s41586-023-05967-z   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2023/05/230524181901.htm   
      
   --- up 1 year, 12 weeks, 2 days, 10 hours, 50 minutes   
    * Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)   
   SEEN-BY: 15/0 106/201 114/705 123/120 153/7715 218/700 226/30 227/114   
   SEEN-BY: 229/110 112 113 307 317 400 426 428 470 664 700 291/111 292/854   
   SEEN-BY: 298/25 305/3 317/3 320/219 396/45   
   PATH: 317/3 229/426