Superconductivity yog ib qho xwm txheej uas lub zog hluav taws xob ntawm cov khoom siv poob rau xoom ntawm qee qhov kub tseem ceeb. Lub tswv yim Bardeen-Cooper-Schrieffer (BCS) yog ib qho kev piav qhia zoo, uas piav qhia txog superconductivity hauv feem ntau cov khoom siv. Nws taw qhia tias Cooper electron khub tau tsim nyob rau hauv lub lattice siv lead ua ntawm qhov kub qis txaus, thiab tias BCS superconductivity los ntawm lawv cov condensation. Txawm hais tias graphene nws tus kheej yog tus neeg coj hluav taws xob zoo heev, nws tsis qhia BCS superconductivity vim yog kev txwv ntawm kev sib cuam tshuam electron-phonon. Qhov no yog vim li cas feem ntau "zoo" conductors (xws li kub thiab tooj liab) yog "phem" superconductors.
Cov kws tshawb fawb ntawm Lub Chaw rau Theoretical Physics ntawm Complex Systems (PCS) ntawm Lub Tsev Kawm Ntawv ntawm Kev Tshawb Fawb Qib Siab (IBS, Kaus Lim Qab Teb) tau tshaj tawm txog lwm txoj hauv kev tshiab los ua kom tiav superconductivity hauv graphene. Lawv ua tiav qhov kev ua tiav no los ntawm kev thov kom muaj lub kaw lus sib xyaw ua ke ntawm graphene thiab ob-seem Bose-Einstein condensate (BEC). Cov kev tshawb fawb tau luam tawm hauv phau ntawv xov xwm 2D Materials.
Ib lub cev sib xyaw ua ke uas muaj cov pa roj electron (txheej sab saud) hauv graphene, sib cais los ntawm ob-seem Bose-Einstein condensate, uas sawv cev los ntawm indirect excitons (txheej xiav thiab liab). Cov electrons thiab excitons hauv graphene raug txuas los ntawm Coulomb force.
(a) Qhov kub thiab txias nyob ntawm qhov sib txawv ntawm superconducting hauv cov txheej txheem bogolon-mediated nrog kev kho qhov kub thiab txias (kab dashed) thiab tsis muaj kev kho qhov kub thiab txias (kab khoom). (b) Qhov kub tseem ceeb ntawm kev hloov pauv superconducting ua ib qho haujlwm ntawm qhov ceev ntawm condensate rau kev sib cuam tshuam bogolon-mediated nrog (kab liab dashed) thiab tsis muaj (kab khoom dub) kev kho qhov kub thiab txias. Kab xiav dotted qhia qhov kub thiab txias hloov pauv BKT ua ib qho haujlwm ntawm qhov ceev ntawm condensate.
Ntxiv rau qhov superconductivity, BEC yog lwm qhov xwm txheej uas tshwm sim ntawm qhov kub qis. Nws yog lub xeev thib tsib ntawm cov khoom thawj zaug kwv yees los ntawm Einstein hauv xyoo 1924. Kev tsim ntawm BEC tshwm sim thaum cov atoms qis zog sib sau ua ke thiab nkag mus rau tib lub xeev zog, uas yog ib qho kev tshawb fawb dav dav hauv cov khoom siv condensed. Lub cev sib xyaw Bose-Fermi feem ntau sawv cev rau kev sib cuam tshuam ntawm ib txheej ntawm cov electrons nrog ib txheej ntawm bosons, xws li cov excitons tsis ncaj qha, exciton-polarons, thiab lwm yam. Kev sib cuam tshuam ntawm Bose thiab Fermi cov khoom me me ua rau muaj ntau yam tshiab thiab txaus nyiam tshwm sim, uas ua rau muaj kev txaus siab ntawm ob tog. Kev pom yooj yim thiab daim ntawv thov.
Hauv txoj haujlwm no, cov kws tshawb fawb tau tshaj tawm txog lub tshuab ua kom muaj zog tshiab hauv graphene, uas yog vim muaj kev sib cuam tshuam ntawm cov electrons thiab "bogolons" es tsis yog cov phonons hauv ib qho system BCS. Bogolons lossis Bogoliubov quasiparticles yog cov excitations hauv BEC, uas muaj qee yam ntxwv ntawm cov khoom me me. Hauv qee qhov parameter ranges, lub tshuab no tso cai rau qhov kub thiab txias tseem ceeb hauv graphene kom ncav cuag siab txog 70 Kelvin. Cov kws tshawb fawb kuj tau tsim ib txoj kev tshawb fawb BCS tshiab uas tsom mus rau cov kab ke raws li graphene hybrid tshiab. Tus qauv uas lawv tau thov kuj kwv yees tias cov khoom superconducting tuaj yeem nce nrog qhov kub thiab txias, ua rau muaj kev vam khom kub tsis yog monotonic ntawm qhov sib txawv superconducting.
Ntxiv rau, kev tshawb fawb tau qhia tias Dirac dispersion ntawm graphene tau khaws cia rau hauv txoj kev npaj bogolon-mediated no. Qhov no qhia tau hais tias cov txheej txheem superconducting no cuam tshuam nrog cov electrons nrog relativistic dispersion, thiab qhov tshwm sim no tsis tau raug tshawb nrhiav zoo hauv cov khoom siv condensed.
Cov haujlwm no qhia txog lwm txoj hauv kev los ua kom tau qhov kub siab superconductivity. Tib lub sijhawm, los ntawm kev tswj cov khoom ntawm cov condensate, peb tuaj yeem kho qhov superconductivity ntawm graphene. Qhov no qhia txog lwm txoj hauv kev los tswj cov khoom siv superconducting yav tom ntej.
Lub sijhawm tshaj tawm: Lub Xya Hli-16-2021 
