Superconductivity yog ib qho tshwm sim ntawm lub cev uas qhov hluav taws xob tsis kam ntawm cov khoom poob mus rau xoom ntawm qhov kub thiab txias.Bardeen-Cooper-Schrieffer (BCS) txoj kev xav yog ib qho kev piav qhia zoo, uas piav qhia txog cov khoom siv hluav taws xob ntau hauv cov khoom siv.Nws taw qhia tias Cooper electron khub yog tsim nyob rau hauv siv lead ua lattice ntawm qhov kub txaus, thiab tias BCS superconductivity los ntawm lawv cov condensation.Txawm hais tias graphene nws tus kheej yog ib qho khoom siv hluav taws xob zoo heev, nws tsis pom BCS superconductivity vim kev cuam tshuam ntawm electron-phonon kev sib cuam tshuam.Qhov no yog vim li cas feem ntau "zoo" conductors (xws li kub thiab tooj liab) yog "phem" superconductors.
Cov kws tshawb fawb ntawm Center for Theoretical Physics of Complex Systems (PCS) ntawm lub koom haum ntawm Basic Science (IBS, South Kauslim) tau tshaj tawm cov txheej txheem tshiab rau kev ua tiav superconductivity hauv graphene.Lawv tau ua tiav qhov kev ua tau zoo los ntawm kev tawm tswv yim txog kev sib xyaw ua ke ntawm graphene thiab ob-seem Bose-Einstein condensate (BEC).Cov kev tshawb fawb tau luam tawm nyob rau hauv phau ntawv journal 2D Materials.
Cov txheej txheem hybrid uas muaj cov roj hluav taws xob (sab saum toj txheej) hauv graphene, sib cais los ntawm ob sab ntawm Bose-Einstein condensate, sawv cev los ntawm kev tsis ncaj ncees excitons (xiav thiab liab txheej).Cov electrons thiab excitons hauv graphene yog ua ke los ntawm Coulomb quab yuam.
(a) Qhov kub ntawm qhov sib txawv ntawm qhov sib txawv superconducting nyob rau hauv cov txheej txheem bogolon-mediated nrog kev kho qhov kub thiab txias (dashed kab) thiab tsis muaj kev kho qhov kub thiab txias (khoom kab).(b) Qhov ntsuas kub tseem ceeb ntawm kev hloov pauv ntawm superconducting raws li kev ua haujlwm ntawm condensate ntom rau bogolon-mediated kev sib cuam tshuam nrog (liab dashed kab) thiab tsis muaj (dub khoom kab) kub kho.Cov kab xiav dotted qhia txog BKT kev hloov pauv kub raws li kev ua haujlwm ntawm condensate ntom.
Ntxiv rau superconductivity, BEC yog lwm qhov tshwm sim uas tshwm sim ntawm qhov kub thiab txias.Nws yog lub xeev thib tsib ntawm qhov teeb meem thawj zaug tau kwv yees los ntawm Einstein hauv xyoo 1924. Kev tsim ntawm BEC tshwm sim thaum lub zog qis atoms sib sau ua ke thiab nkag mus rau tib lub zog, uas yog ib qho kev tshawb fawb dav dav hauv cov teeb meem condensed physics.Lub hybrid Bose-Fermi system tseem ceeb sawv cev rau kev sib cuam tshuam ntawm ib txheej ntawm electrons nrog ib txheej ntawm bosons, xws li indirect excitons, exciton-polarons, thiab hais txog.Kev sib cuam tshuam ntawm Bose thiab Fermi hais coj mus rau ntau yam tshiab thiab ntxim nyiam tshwm sim, uas ua rau muaj kev txaus siab ntawm ob tog.Basic thiab daim ntawv thov-oriented saib.
Hauv kev ua haujlwm no, cov kws tshawb fawb tau tshaj tawm cov txheej txheem tshiab superconducting hauv graphene, uas yog vim muaj kev cuam tshuam ntawm cov hluav taws xob thiab "bogolons" es tsis yog cov phonons hauv cov txheej txheem BCS.Bogolons los yog Bogoliubov quasiparticles yog excitations nyob rau hauv BEC, uas muaj tej yam ntxwv ntawm hais.Hauv qee qhov kev txwv tsis pub dhau, qhov txheej txheem no tso cai rau qhov ntsuas kub tseem ceeb hauv graphene kom ncav cuag li 70 Kelvin.Cov kws tshawb fawb kuj tau tsim ib txoj kev tshawb fawb microscopic BCS tshiab uas tshwj xeeb tsom rau cov tshuab raws li cov hybrid graphene tshiab.Cov qauv uas lawv tau npaj los kuj tau kwv yees tias cov khoom siv hluav taws xob superconducting tuaj yeem nce nrog qhov kub thiab txias, ua rau qhov tsis muaj qhov kub ntawm qhov sib txawv ntawm qhov sib txawv superconducting.
Tsis tas li ntawd, cov kev tshawb fawb tau pom tias Dirac dispersion ntawm graphene yog khaws cia nyob rau hauv no bogolon-mediated scheme.Qhov no qhia tau hais tias qhov no superconducting mechanism muaj xws li electrons nrog relativistic dispersion, thiab qhov tshwm sim no tsis tau tshawb pom zoo nyob rau hauv condensed teeb meem physics.
Txoj haujlwm no nthuav tawm lwm txoj hauv kev kom ua tiav qhov kub-kub superconductivity.Nyob rau tib lub sijhawm, los ntawm kev tswj cov khoom ntawm condensate, peb tuaj yeem kho cov superconductivity ntawm graphene.Qhov no qhia tau lwm txoj hauv kev los tswj cov khoom siv superconducting yav tom ntej.
Post lub sij hawm: Lub Xya hli ntuj-16-2021 
