{"id":20284,"date":"2011-08-30T19:30:59","date_gmt":"2011-08-30T16:30:59","guid":{"rendered":"http:\/\/www.fyysika.ee\/uudised\/?p=20284"},"modified":"2011-09-02T10:05:49","modified_gmt":"2011-09-02T07:05:49","slug":"avastati-eksootiline-kvantkristall-2","status":"publish","type":"post","link":"https:\/\/www.fyysika.ee\/?p=20284","title":{"rendered":"Avastati eksootiline kvantkristall"},"content":{"rendered":"<p><strong>Looduses eksisteerib kahte sorti tahkiseid. \u00dched neist tekivad vedelike kokku surumisel, teised aga vedelike siser\u00f5hu v\u00e4hendamisel. Esimene variant on igap\u00e4evaelus h\u00e4sti tuntud, n\u00e4iteks kuiva j\u00e4\u00e4 varal (loe <a href=\"http:\/\/en.wikipedia.org\/wiki\/Dry_ice\">siit<\/a>). Teine vairant avaldub n\u00e4iteks tiheda elektronide kvantvedelikuna metallides v\u00f5i ioonidena valges k\u00e4\u00e4buses v\u00f5i neutront\u00e4hes. N\u00fc\u00fcd ennustati, et eksisteerib veel kolmaski mateeria vorm, mis kombineerib m\u00f5lemad eelmainitud omadused.<\/strong><\/p>\n<p>Ebatavalisi omadusi k\u00e4tkeb tugevasse elektriv\u00e4lja asetatud potentsiaalibarj\u00e4\u00e4ris olev eksitonide kristall. Eksiton on seotud elektron-auk (elektronkihi vakants) paar tahkises.<\/p>\n<div id=\"attachment_20285\" style=\"width: 270px\" class=\"wp-caption alignleft\"><a href=\"http:\/\/www.fyysika.ee\/uudised\/wp-content\/uploads\/2011\/08\/eksitonkristall.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-20285\" class=\"size-full wp-image-20285\" src=\"http:\/\/www.fyysika.ee\/uudised\/wp-content\/uploads\/2011\/08\/eksitonkristall.jpg\" alt=\"\" width=\"260\" height=\"261\" srcset=\"https:\/\/www.fyysika.ee\/wp-content\/uploads\/2011\/08\/eksitonkristall.jpg 260w, https:\/\/www.fyysika.ee\/wp-content\/uploads\/2011\/08\/eksitonkristall-150x150.jpg 150w, https:\/\/www.fyysika.ee\/wp-content\/uploads\/2011\/08\/eksitonkristall-250x250.jpg 250w\" sizes=\"auto, (max-width: 260px) 100vw, 260px\" \/><\/a><p id=\"caption-attachment-20285\" class=\"wp-caption-text\">Piltidel on kujutatud kvantosakesed ehk eksitonid kvantiseeritud potentsiaalibarj\u00e4\u00e4ris. Kollase v\u00e4rviga on t\u00e4histatud suur, punasega madalam ja rohelisega null eksitonide tihedus. Vaadates kaht heledamat joonist on n\u00e4ha eksitonide tiheduse kasv konstantsel temperatuuril. <\/p><\/div>\n<p>Kieli \u00dclikooli teadlastest koosnev t\u00f6\u00f6r\u00fchm viis uue materjali omaduste avastamiseks l\u00e4bi ulatuslikke t\u00e4pseid arvutisimulatsioone. Tulemused avaldatakse ajakirjas <em>Physical Review B<\/em>, milles seletatakse \u00fchtlasi kahe n\u00e4iliselt vastuolulise sulamisprotsessi iseloom.<\/p>\n<p>Uue materjali olemust seletab kahe eksitoni vaheliste j\u00f5udude olemus. Madalatel r\u00f5hkudel eksitonid t\u00f5ukuvad dipoolmomentide t\u00f5ttu ja moodustavad kvantvedeliku. R\u00f5hu kasvades toimub vedeliku kristalliks tahkestumine. Edasine survestamine viib eksitonid sedav\u00f5rd l\u00e4hestikku, et nende elektronide ja aukude leiulained kattuvad ja hakkavad dipoolmomentide j\u00f5udusid n\u00f5rgestama.<\/p>\n<p>R\u00f5hu kasvamise t\u00f5ttu tekib eksitonide seisulainete kattuvus, mida eksitoni dipoolmomendid enam kompenseerida ei suuda \u2013 kristall hakkab taas sulama. Teadlased on teinud eksitonkristallide leidmiseks t\u00e4pseid ennustusi. Eriti hoolikalt on uuritud tsink-seleeni ja gallium-arseniidi kvantpotentsiaalibarj\u00e4\u00e4re. J\u00e4\u00e4b \u00fcle vaid kristallid eksperimentaalselt avastada.<\/p>\n<p>Allikas: <a href=\"http:\/\/www.physorg.com\/news\/2011-08-exotic-quantum-crystal.html\">PhysOrg<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Looduses eksisteerib kahte sorti tahkiseid. \u00dched neist tekivad vedelike kokku surumisel, teised aga vedelike siser\u00f5hu v\u00e4hendamisel. Esimene variant on igap\u00e4evaelus h\u00e4sti tuntud, n\u00e4iteks kuiva j\u00e4\u00e4 varal (loe siit). Teine vairant avaldub n\u00e4iteks tiheda elektronide kvantvedelikuna metallides v\u00f5i ioonidena valges k\u00e4\u00e4buses v\u00f5i neutront\u00e4hes. N\u00fc\u00fcd ennustati, et eksisteerib veel kolmaski mateeria vorm, mis kombineerib m\u00f5lemad eelmainitud omadused. [&hellip;]<\/p>\n","protected":false},"author":449,"featured_media":20285,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_genesis_hide_title":false,"_genesis_hide_breadcrumbs":false,"_genesis_hide_singular_image":false,"_genesis_hide_footer_widgets":false,"_genesis_custom_body_class":"","_genesis_custom_post_class":"","_genesis_layout":"","footnotes":""},"categories":[16],"tags":[110],"class_list":{"0":"post-20284","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-teadusuudis","8":"tag-materjal","9":"entry"},"_links":{"self":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/20284","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/users\/449"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=20284"}],"version-history":[{"count":0,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/20284\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/media\/20285"}],"wp:attachment":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=20284"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=20284"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=20284"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}