{"id":9769,"date":"2026-02-06T15:31:46","date_gmt":"2026-02-06T14:31:46","guid":{"rendered":"https:\/\/websrv.saske.sk\/uef\/?p=9769"},"modified":"2026-02-06T15:31:46","modified_gmt":"2026-02-06T14:31:46","slug":"2d-fyzika-realizovana-v-3d-krystaloch-narusenim-ich-inverznej-symetrie","status":"publish","type":"post","link":"https:\/\/websrv.saske.sk\/uef\/2d-fyzika-realizovana-v-3d-krystaloch-narusenim-ich-inverznej-symetrie\/","title":{"rendered":"2D fyzika realizovan\u00e1 v 3D kry\u0161t\u00e1loch naru\u0161en\u00edm ich inverznej symetrie"},"content":{"rendered":"

Dvojrozmern\u00e9 (2D) materi\u00e1ly vo v\u0161eobecnosti umo\u017e\u0148uj\u00fa realiz\u00e1ciu jedine\u010dn\u00fdch kvantov\u00fdch javov, ktor\u00e9 s\u00fa v be\u017enom trojrozmernom (3D) svete nedosiahnute\u013en\u00e9. Typick\u00fdm pr\u00edkladom je graf\u00e9n. Prechodov\u00e9 kovov\u00e9 dichalkogenidy (TMD) maj\u00fa podobn\u00fa \u0161trukt\u00faru. Obe triedy materi\u00e1lov mo\u017eno vrstvi\u0165 do van der Waalsov\u00fdch hetero\u0161trukt\u00far alebo exfoliova\u0165 na jednotliv\u00e9 vrstvy. TMD v\u0161ak pon\u00fakaj\u00fa aj \u0161ir\u0161iu \u0161k\u00e1lu vynikaj\u00facich vlastnost\u00ed, vr\u00e1tane silnej spin-orbit\u00e1lnej v\u00e4zby a supravodivosti. V 2D (jednovrstvovom at\u00f3movom filme) NbSe\u2082, ktor\u00fd je v\u00fdznamn\u00fdm z\u00e1stupcom TMD, vedie kombin\u00e1cia t\u00fdchto dvoch efektov spolu so \u0161pecifickou kry\u0161t\u00e1lovou symetriou k tzv. Isingovej supravodivosti (IS), ktor\u00e1 dok\u00e1\u017ee odola\u0165 extr\u00e9mne vysok\u00fdm magnetick\u00fdm poliam orientovan\u00fdm rovnobe\u017ene s rovinou kry\u0161t\u00e1lu. E\u0161te vzru\u0161uj\u00facej\u0161ie ne\u017e t\u00e1to odolnos\u0165 vo\u010di magnetick\u00fdm poliam je potenci\u00e1lne vyu\u017eitie IS pri realiz\u00e1cii r\u00f4znych exotick\u00fdch javov, ako s\u00fa Andreevova reflexia s rovnak\u00fdm spinom, topologick\u00e1 supravodivos\u0165 a Majoranove fermi\u00f3ny.<\/p>\n

2D \u0161trukt\u00fary s\u00fa v\u0161ak n\u00e1chyln\u00e9 na degrad\u00e1ciu a nepraktick\u00e9 pre aplik\u00e1cie. Naopak, 3D materi\u00e1ly s\u00fa robustn\u00e9, \u013eahko \u0161k\u00e1lovate\u013en\u00e9 a pr\u00edstupn\u00e9 \u0161ir\u0161iemu spektru vedeck\u00fdch analytick\u00fdch techn\u00edk. Preto je \u017eiaduce n\u00e1js\u0165 sp\u00f4soby, ako zachova\u0165 jedine\u010dn\u00e9 vlastnosti 2D materi\u00e1lov v ich 3D n\u00e1protivkoch. Be\u017enou strat\u00e9giou, ako \u201evlo\u017ei\u0165\u201c 2D spr\u00e1vanie do 3D TMD, je interkal\u00e1cia funk\u010dn\u00fdch vrstiev medzi TMD at\u00f3mov\u00e9 vrstvy. Ako ukazuje rast\u00faci po\u010det publikovan\u00fdch \u010dl\u00e1nkov, tak\u00e9to interkalovan\u00e9 3D materi\u00e1ly vykazuj\u00fa medzivrstvov\u00fa vodivos\u0165, ale zachov\u00e1vaj\u00fa si vlastnosti 2D TMD, vr\u00e1tane IS. Hoci je tento pr\u00edstup \u00fa\u010dinn\u00fd, interkal\u00e1cia komplikuje syst\u00e9m a m\u00f4\u017ee vies\u0165 k \u010fal\u0161\u00edm efektom.<\/p>\n

Jednoduch\u0161ia cesta: in\u017einiering symetrie, nie ch\u00e9mia<\/strong><\/p>\n

Vo svojej novej \u0161t\u00fadii t\u00edm z Ko\u0161\u00edc ukazuje, \u017ee interkal\u00e1cia nie je nevyhnutn\u00e1. Ich pr\u00e1ca publikovan\u00e1 vo Physical Review Letters<\/em><\/strong> demon\u0161truje, \u017ee existuje priamo\u010diarej\u0161\u00ed postup ku podobn\u00fdm v\u00fdsledkom. Na ochranu IS v objemovom kry\u0161t\u00e1li NbSe\u2082 posta\u010duje samotn\u00e9 poru\u0161enie inverznej symetrie inak centro-symetrickej kry\u0161t\u00e1lovej mrie\u017eky, a to bez akejko\u013evek interkal\u00e1cie. Na rozdiel od be\u017en\u00e9ho 2H-NbSe2<\/sub> kry\u0161t\u00e1lu mo\u017eno pri vy\u0161\u0161ej teplote pripravi\u0165 4Ha<\/sub>-NbSe2<\/sub> polytyp, ktor\u00fd m\u00e1 \u0161tyri at\u00f3mov\u00e9 roviny v primit\u00edvnej bunke (pozri obr\u00e1zok) a tie maj\u00fa poru\u0161en\u00fa symetriu,<\/p>\n

Ke\u010f\u017ee rozdiel medzi dvoma polytypmi je jemn\u00fd, autori najprv pou\u017eili r\u00f4zne experiment\u00e1lne techniky na jednozna\u010dn\u00e9 ur\u010denie kry\u0161t\u00e1lovej \u0161trukt\u00fary vzorky. N\u00e1sledne pomocou meran\u00ed tepelnej kapacity preuk\u00e1zali, \u017ee objemov\u00e1 supravodivos\u0165 v monokry\u0161t\u00e1li 4Ha<\/sub>-NbSe\u2082 odol\u00e1va magnetick\u00fdm poliam takmer trikr\u00e1t vy\u0161\u0161\u00edm, ne\u017e je Pauliho limit. Merania tepelnej kapacity charakterizuj\u00fa objemov\u00e9 vlastnosti vzorky; preto s\u00fa nadraden\u00e9 transportn\u00fdm meraniam pou\u017eit\u00fdm v predch\u00e1dzaj\u00facich \u0161t\u00fadi\u00e1ch, ktor\u00e9 m\u00f4\u017eu trpie\u0165 r\u00f4znymi parazitn\u00fdmi 2D efektmi. Napokon, s vyu\u017eit\u00edm z\u00edskan\u00fdch kry\u0161talografick\u00fdch parametrov autori ab initio<\/em> vypo\u010d\u00edtali p\u00e1sov\u00fa \u0161trukt\u00faru polytypu 4Ha-NbSe\u2082 a\u00a0dok\u00e1zali pr\u00edtomnos\u0165 IS v\u00a0takomto kry\u0161t\u00e1li.<\/p>\n

Pre\u010do je to d\u00f4le\u017eit\u00e9<\/strong><\/p>\n

Tieto v\u00fdsledky ukazuj\u00fa, \u017ee usporiadanie vrstiev a symetria \u2013 nielen chemick\u00e9 zlo\u017eenie \u2013 m\u00f4\u017eu by\u0165 pou\u017eit\u00e9 na ladenie z\u00e1kladn\u00fdch elektronick\u00fdch vlastnost\u00ed v objemov\u00fdch TMD. Tento pr\u00edstup zjednodu\u0161uje n\u00e1vrh materi\u00e1lov, vyh\u00fdba sa chemickej komplexnosti a pon\u00faka robustn\u00fa, \u0161k\u00e1lovate\u013en\u00fa platformu na sk\u00famanie a vyu\u017eitie Isingovej supravodivosti v realistick\u00fdch zariadeniach. Otv\u00e1ra nov\u00e9 cesty.<\/p>\n

 <\/p>\n

Obr\u00e1zok:<\/strong><\/p>\n

Tepeln\u00e1 kapacita kry\u0161t\u00e1lu 4Ha<\/sub>-NbSe\u2082 meran\u00e1 a\u017e do 19 T. Vlo\u017een\u00fd obr\u00e1zok: Kry\u0161t\u00e1lov\u00e1 \u0161trukt\u00fara 4Ha<\/sub>-NbSe\u2082, kde element\u00e1rna bunka pozost\u00e1va zo 4 vrstiev<\/p>\n

 <\/p>\n

DOI: https:\/\/doi.org\/10.1103\/qxb4-sf28<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Dvojrozmern\u00e9 (2D) materi\u00e1ly vo v\u0161eobecnosti umo\u017e\u0148uj\u00fa realiz\u00e1ciu jedine\u010dn\u00fdch kvantov\u00fdch javov, ktor\u00e9 s\u00fa v be\u017enom trojrozmernom (3D) svete nedosiahnute\u013en\u00e9. Typick\u00fdm pr\u00edkladom je graf\u00e9n. Prechodov\u00e9 kovov\u00e9 dichalkogenidy…<\/p>\n","protected":false},"author":11,"featured_media":9770,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"_links":{"self":[{"href":"https:\/\/websrv.saske.sk\/uef\/wp-json\/wp\/v2\/posts\/9769"}],"collection":[{"href":"https:\/\/websrv.saske.sk\/uef\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/websrv.saske.sk\/uef\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/websrv.saske.sk\/uef\/wp-json\/wp\/v2\/users\/11"}],"replies":[{"embeddable":true,"href":"https:\/\/websrv.saske.sk\/uef\/wp-json\/wp\/v2\/comments?post=9769"}],"version-history":[{"count":3,"href":"https:\/\/websrv.saske.sk\/uef\/wp-json\/wp\/v2\/posts\/9769\/revisions"}],"predecessor-version":[{"id":9773,"href":"https:\/\/websrv.saske.sk\/uef\/wp-json\/wp\/v2\/posts\/9769\/revisions\/9773"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/websrv.saske.sk\/uef\/wp-json\/wp\/v2\/media\/9770"}],"wp:attachment":[{"href":"https:\/\/websrv.saske.sk\/uef\/wp-json\/wp\/v2\/media?parent=9769"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/websrv.saske.sk\/uef\/wp-json\/wp\/v2\/categories?post=9769"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/websrv.saske.sk\/uef\/wp-json\/wp\/v2\/tags?post=9769"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}