Kuchuluka kwa mphamvu zamagetsi ndi chinthu chomwe chimachititsa kuti kukana kwa magetsi kwa chinthu kuchepe kufika pa zero pa kutentha kofunikira. Chiphunzitso cha Bardeen-Cooper-Schrieffer (BCS) ndi kufotokozera kogwira mtima, komwe kumafotokoza kuchuluka kwa mphamvu zamagetsi m'zinthu zambiri. Chimasonyeza kuti mawiri a ma electron a Cooper amapangidwa mu lattice ya kristalo pa kutentha kochepa mokwanira, ndipo kuti kuchuluka kwa mphamvu zamagetsi a BCS kumachokera ku kuuma kwawo. Ngakhale kuti graphene yokha ndi kondakitala wabwino kwambiri wamagetsi, sikuwonetsa mphamvu zamagetsi za BCS chifukwa choletsa kuyanjana kwa ma electron-phonon. Ichi ndichifukwa chake ma kondakitala ambiri "abwino" (monga golide ndi mkuwa) ndi ma superconductor "oyipa".
Ofufuza ku Center for Theoretical Physics of Complex Systems (PCS) ku Institute of Basic Science (IBS, South Korea) adanenanso za njira ina yatsopano yopezera superconductivity mu graphene. Adakwaniritsa izi popereka njira yosakanikirana yopangidwa ndi graphene ndi Bose-Einstein condensate (BEC) yokhala ndi magawo awiri. Kafukufukuyu adasindikizidwa mu magazini ya 2D Materials.
Dongosolo losakanikirana lokhala ndi mpweya wa ma elekitironi (wokhala pamwamba) mu graphene, wolekanitsidwa ndi condensate ya Bose-Einstein yokhala ndi magawo awiri, yoimiridwa ndi ma exciton osalunjika (magawo abuluu ndi ofiira). Ma elekitironi ndi ma exciton mu graphene amalumikizidwa ndi mphamvu ya Coulomb.
(a) Kudalira kutentha kwa kusiyana kwa superconducting mu njira yolumikizirana ndi bogolon ndi kukonza kutentha (mzere wodulidwa) komanso popanda kukonza kutentha (mzere wolimba). (b) Kutentha kofunikira kwa kusintha kwa superconducting monga momwe zimakhalira ndi kuchuluka kwa condensate pakugwirizanitsa kwa bogolon ndi (mzere wofiira wodulidwa) komanso popanda (mzere wakuda wolimba) kutentha. Mzere wabuluu wokhala ndi madontho umasonyeza kutentha kwa kusintha kwa BKT ngati momwe zimakhalira ndi kuchuluka kwa condensate.
Kuwonjezera pa superconductivity, BEC ndi chinthu china chomwe chimachitika kutentha kochepa. Ndi mkhalidwe wachisanu wa chinthu chomwe chinanenedweratu koyamba ndi Einstein mu 1924. Kupangidwa kwa BEC kumachitika pamene maatomu a mphamvu zochepa amasonkhana pamodzi ndikulowa mu mkhalidwe womwewo wa mphamvu, womwe ndi gawo la kafukufuku wochuluka mu fizikisi ya zinthu zozungulira. Dongosolo la hybrid Bose-Fermi kwenikweni limayimira kuyanjana kwa wosanjikiza wa ma electron ndi wosanjikiza wa ma bosons, monga ma exciton osalunjika, ma exciton-polaron, ndi zina zotero. Kuyanjana pakati pa tinthu ta Bose ndi Fermi kunatsogolera ku zochitika zosiyanasiyana zatsopano komanso zosangalatsa, zomwe zinadzutsa chidwi cha mbali zonse ziwiri. Mawonedwe oyambira komanso olunjika pa ntchito.
Mu ntchito iyi, ofufuzawo adanenanso za njira yatsopano yopangira zinthu mu graphene, yomwe imachitika chifukwa cha kuyanjana pakati pa ma elekitironi ndi "ma bogolon" m'malo mwa ma phononi omwe ali mu dongosolo la BCS. Ma Bogolon kapena ma Bogoliubov quasiparticles ndi zinthu zochititsa chidwi mu BEC, zomwe zimakhala ndi makhalidwe enaake a tinthu tating'onoting'ono. M'malo enaake, njira imeneyi imalola kutentha kofunikira kwa superconducting mu graphene kufika pa 70 Kelvin. Ofufuza apanganso chiphunzitso chatsopano cha microscopic BCS chomwe chimayang'ana kwambiri machitidwe ozikidwa pa graphene yatsopano yosakanikirana. Chitsanzo chomwe adapereka chikuwonetsanso kuti mphamvu zopangira zinthu zimatha kuwonjezeka ndi kutentha, zomwe zimapangitsa kuti kutentha kwa superconducting kudalira kutentha kosasintha kwa monotonic.
Kuphatikiza apo, kafukufuku wasonyeza kuti kufalikira kwa Dirac kwa graphene kumasungidwa mu dongosolo ili lothandizidwa ndi bogolon. Izi zikusonyeza kuti njira yoyendetsera zinthu imeneyi imagwiritsa ntchito ma elekitironi okhala ndi kufalikira kwa relativistic, ndipo chodabwitsachi sichinafufuzidwe bwino mu fizikisi ya zinthu zofupikitsidwa.
Ntchitoyi ikuwonetsa njira ina yopezera mphamvu yowongolera kutentha kwambiri. Nthawi yomweyo, powongolera mawonekedwe a condensate, titha kusintha mphamvu yowongolera ya graphene. Izi zikuwonetsa njira ina yowongolera zida zowongolera kutentha kwambiri mtsogolo.
Nthawi yotumizira: Julayi-16-2021 
