{"id":4639,"date":"2015-12-07T11:10:29","date_gmt":"2015-12-07T04:10:29","guid":{"rendered":"http:\/\/ttud.com.vn\/?p=4639"},"modified":"2017-10-04T08:50:47","modified_gmt":"2017-10-04T01:50:47","slug":"cac-nha-vat-ly-hoc-vua-phat-hien-mot-trang-thai-pha-moi-la-cua-vat-chat","status":"publish","type":"post","link":"https:\/\/casta.ttud.com.vn\/index.php\/cac-nha-vat-ly-hoc-vua-phat-hien-mot-trang-thai-pha-moi-la-cua-vat-chat\/","title":{"rendered":"C\u00e1c nh\u00e0 v\u1eadt l\u00fd h\u1ecdc v\u1eeba ph\u00e1t hi\u1ec7n m\u1ed9t tr\u1ea1ng th\u00e1i pha m\u1edbi l\u1ea1 c\u1ee7a v\u1eadt ch\u1ea5t"},"content":{"rendered":"

Hsieh, GS V\u1eadt l\u00fd h\u1ecdc, ng\u01b0\u1eddi tr\u01b0\u1edbc \u0111\u00e2y \u0111\u00e3 t\u1eebng tham gia m\u1ed9t nh\u00f3m nghi\u00ean c\u1ee9u ph\u00e1t hi\u1ec7n m\u1ed9t tr\u1ea1ng th\u00e1i kh\u00e1c c\u1ee7a v\u1eadt ch\u1ea5t c\u00f3 t\u00ean l\u00e0 ch\u1ea5t c\u00e1ch \u0111i\u1ec7n d\u1ea1ng t\u00f4 p\u00f4, cho bi\u1ebft “Vi\u1ec7c ph\u00e1t hi\u1ec7n ra pha tr\u1ea1ng th\u00e1i n\u00e0y ho\u00e0n to\u00e0n kh\u00f4ng c\u00f3 ch\u1ee7 \u0111\u00edch v\u00e0 kh\u00f4ng d\u1ef1a tr\u00ean b\u1ea5t k\u1ef3 d\u1ef1 \u0111o\u00e1n mang t\u00ednh l\u00fd thuy\u1ebft n\u00e0o tr\u01b0\u1edbc \u0111\u00f3. To\u00e0n b\u1ed9 l\u0129nh v\u1ef1c v\u1eadt li\u1ec7u \u0111i\u1ec7n t\u1eed \u0111\u01b0\u1ee3c \u0111\u1ecbnh h\u01b0\u1edbng b\u1edfi vi\u1ec7c ph\u00e1t hi\u1ec7n c\u00e1c pha tr\u1ea1ng th\u00e1i m\u1edbi, t\u1eeb \u0111\u00f3 cung c\u1ea5p c\u01a1 s\u1edf cho vi\u1ec7c nghi\u00ean c\u1ee9u t\u00ednh ch\u1ea5t v\u1eadt l\u00fd v\u0129 m\u00f4 ho\u00e0n to\u00e0n m\u1edbi”.<\/strong><\/p>\n

\"\"<\/p>\n

Hsieh c\u00f9ng c\u00e1c \u0111\u1ed3ng s\u1ef1 \u0111\u00e3 m\u00f4 t\u1ea3 c\u00e1c ph\u00e1t hi\u1ec7n \u0111\u01b0\u1ee3c \u0111\u0103ng t\u1ea3i trong \u1ea5n b\u1ea3n th\u00e1ng 11 c\u1ee7a t\u1ea1p ch\u00ed Nature Physics, b\u00e0i b\u00e1o n\u00e0y hi\u1ec7n c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c t\u00ecm ki\u1ebfm tr\u00ean m\u1ea1ng Internet. Liuyan Zhao, m\u1ed9t h\u1ecdc gi\u1ea3 nghi\u00ean c\u1ee9u theo ch\u01b0\u01a1ng tr\u00ecnh sau ti\u1ebfn s\u1ef9 trong nh\u00f3m c\u1ee7a Hsieh, l\u00e0 t\u00e1c gi\u1ea3 ch\u00ednh c\u1ee7a b\u00e0i vi\u1ebft n\u00e0y.<\/p>\n

C\u00e1c nh\u00e0 v\u1eadt l\u00fd h\u1ecdc \u0111\u00e3 t\u00ecnh c\u1edd kh\u00e1m ph\u00e1 ra tr\u1ea1ng th\u00e1i pha v\u1eadt ch\u1ea5t n\u00e0y trong qu\u00e1 tr\u00ecnh th\u1eed nghi\u1ec7m m\u1ed9t k\u1ef9 thu\u1eadt \u0111o d\u1ef1a tr\u00ean laser m\u00e0 nh\u00f3m ph\u00e1t tri\u1ec3n g\u1ea7n \u0111\u00e2y nh\u1eb1m t\u00ecm ki\u1ebfm hi\u1ec7n t\u01b0\u1ee3ng g\u1ecdi l\u00e0 tr\u1eadt t\u1ef1 \u0111a c\u1ef1c. \u0110\u1ec3 hi\u1ec3u r\u00f5 v\u1ec1 tr\u1eadt t\u1ef1 \u0111a c\u1ef1c, \u0111\u1ea7u ti\u00ean, c\u1ea7n xem x\u00e9t m\u1ed9t tinh th\u1ec3 v\u1edbi c\u00e1c \u0111i\u1ec7n t\u1eed chuy\u1ec3n \u0111\u1ed9ng xung quanh b\u00ean trong tinh th\u1ec3 \u0111\u00f3. \u1ede m\u1ed7i \u0111i\u1ec1u ki\u1ec7n nh\u1ea5t \u0111\u1ecbnh, c\u00e1c \u0111i\u1ec7n t\u00edch n\u00e0y s\u1ebd x\u1ebfp h\u00e0ng theo m\u1ed9t c\u00e1ch c\u00f3 tr\u1eadt t\u1ef1 l\u1eb7p l\u1ea1i b\u00ean trong tinh th\u1ec3, t\u1ea1o ra pha \u0111i\u1ec7n t\u00edch c\u00f3 tr\u1eadt t\u1ef1. D\u1ea1ng s\u1eafp x\u1ebfp \u0111i\u1ec7n t\u1eed c\u00f3 tr\u1eadt t\u1ef1 n\u00e0y \u0111\u01a1n gi\u1ea3n l\u00e0 m\u1ed9t \u0111\u1ea1i l\u01b0\u1ee3ng v\u00f4 h\u01b0\u1edbng – ch\u1ec9 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c m\u00f4 t\u1ea3 d\u01b0\u1edbi d\u1ea1ng gi\u00e1 tr\u1ecb s\u1ed1 ho\u1eb7c \u0111\u1ed9 l\u1edbn \u0111i\u1ec7n t\u00edch.<\/p>\n

Ngo\u00e0i kh\u1ea3 n\u0103ng t\u00edch \u0111i\u1ec7n, c\u00e1c \u0111i\u1ec7n t\u1eed c\u00f2n c\u00f3 m\u1ee9c \u0111\u1ed9 chuy\u1ec3n \u0111\u1ed9ng t\u1ef1 do \u0111\u01b0\u1ee3c bi\u1ebft \u0111\u1ebfn l\u00e0 spin. Khi c\u00e1c spin x\u1ebfp h\u00e0ng song song v\u1edbi nhau, ch\u00fang t\u1ea1o th\u00e0nh m\u1ed9t ch\u1ea5t s\u1eaft t\u1eeb – m\u1ed9t lo\u1ea1i nam ch\u00e2m m\u00e0 ch\u00fang ta s\u1eed d\u1ee5ng trong ch\u1ebf t\u1ea1o thi\u1ebft b\u1ecb t\u1ee7 l\u1ea1nh ho\u1eb7c c\u00f3 th\u1ec3 t\u00ecm th\u1ea5y tr\u00ean d\u1ea3i t\u1eeb c\u1ee7a th\u1ebb t\u00edn d\u1ee5ng. Do d\u1ea1ng s\u1eafp x\u1ebfp \u0111i\u1ec7n t\u1eed ki\u1ec3u spin n\u00e0y \u0111\u01b0\u1ee3c bi\u1ec3u th\u1ecb b\u1eb1ng c\u1ea3 \u0111\u1ed9 l\u1edbn v\u00e0 h\u01b0\u1edbng, m\u1ed7i pha spin c\u00f3 tr\u1eadt t\u1ef1 \u0111\u01b0\u1ee3c m\u00f4 t\u1ea3 b\u1eb1ng m\u1ed9t vect\u01a1.<\/p>\n

Trong nhi\u1ec1u th\u1eadp k\u1ef7 m\u1edbi \u0111\u00e2y, c\u00e1c nh\u00e0 v\u1eadt l\u00fd h\u1ecdc \u0111\u00e3 x\u00e2y d\u1ef1ng c\u00e1c k\u1ef9 thu\u1eadt tinh vi h\u01a1n nh\u1eb1m t\u00ecm ki\u1ebfm c\u1ea3 hai lo\u1ea1i pha v\u1eadt ch\u1ea5t n\u00e0y. Tuy nhi\u00ean, \u0111i\u1ec1u g\u00ec s\u1ebd x\u1ea3y ra n\u1ebfu c\u00e1c \u0111i\u1ec7n t\u1eed trong v\u1eadt ch\u1ea5t kh\u00f4ng \u0111\u01b0\u1ee3c s\u1eafp x\u1ebfp theo tr\u1eadt t\u1ef1 nh\u01b0 \u0111\u00e3 n\u00f3i \u1edf tr\u00ean? V\u00e0 s\u1ebd ra sao n\u1ebfu tr\u1eadt t\u1ef1 n\u00e0y \u0111\u01b0\u1ee3c m\u00f4 t\u1ea3 kh\u00f4ng b\u1eb1ng m\u1ed9t vect\u01a1 c\u00f3 h\u01b0\u1edbng hay m\u1ed9t thu\u1ed9c t\u00ednh v\u00f4 h\u01b0\u1edbng m\u00e0 l\u00e0 b\u1eb1ng m\u1ed9t d\u1ea1ng c\u00f3 nhi\u1ec1u h\u1ea1ng b\u1eadc h\u01a1n, ch\u1eb3ng h\u1ea1n nh\u01b0 m\u1ed9t ma tr\u1eadn? \u0110i\u1ec1u n\u00e0y c\u00f3 th\u1ec3 x\u1ea3y ra n\u1ebfu d\u1ea1ng s\u1eafp x\u1ebfp \u0111i\u1ec7n t\u1eed c\u00f3 tr\u1eadt t\u1ef1 n\u00e0y l\u00e0 m\u1ed9t c\u1eb7p \u0111i\u1ec7n t\u1eed c\u00f3 spin \u0111\u1ed1i l\u1eadp – m\u1ed9t ch\u1ec9 v\u1ec1 h\u01b0\u1edbng b\u1eafc v\u00e0 m\u1ed9t ch\u1ec9 v\u1ec1 h\u01b0\u1edbng nam – hay c\u00f2n \u0111\u01b0\u1ee3c bi\u1ebft \u0111\u1ebfn l\u00e0 nam ch\u00e2m t\u1ee9 c\u1ef1c. V\u00ed d\u1ee5 minh h\u1ecda cho c\u00e1c pha v\u1eadt ch\u1ea5t \u0111a c\u1ef1c c\u00f3 tr\u1eadt t\u1ef1 n\u00e0y kh\u00f3 c\u00f3 th\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng \u0111\u1ea7u d\u00f2 th\u1ef1c nghi\u1ec7m truy\u1ec1n th\u1ed1ng.<\/p>\n

\u0110\u1ec3 x\u00e1c \u0111\u1ecbnh tr\u1eadt t\u1ef1 \u0111a c\u1ef1c, nh\u00f3m c\u1ee7a Hsieh \u0111\u00e3 s\u1eed d\u1ee5ng m\u1ed9t hi\u1ec7u \u1ee9ng g\u1ecdi l\u00e0 h\u1ecda \u00e2m quang h\u1ecdc, th\u01b0\u1eddng th\u1ea5y \u1edf t\u1ea5t c\u1ea3 c\u00e1c v\u1eadt li\u1ec7u r\u1eafn nh\u01b0ng th\u01b0\u1eddng th\u00ec c\u1ef1c k\u1ef3 y\u1ebfu. Th\u00f4ng th\u01b0\u1eddng, khi ta nh\u00ecn v\u00e0o m\u1ed9t v\u1eadt \u0111\u01b0\u1ee3c chi\u1ebfu s\u00e1ng b\u1edfi m\u1ed9t t\u1ea7n su\u1ea5t \u00e1nh s\u00e1ng duy nh\u1ea5t, t\u1ea5t c\u1ea3 \u00e1nh s\u00e1ng m\u00e0 ta nh\u00ecn th\u1ea5y \u0111\u01b0\u1ee3c ph\u1ea3n chi\u1ebfu t\u1eeb v\u1eadt \u1edf t\u1ea1i t\u1ea7n s\u1ed1 \u0111\u00f3. Ch\u1eb3ng h\u1ea1n, khi ta chi\u1ebfu m\u1ed9t tia laser m\u00e0u \u0111\u1ecf v\u00e0o m\u1ed9t b\u1ee9c t\u01b0\u1eddng, m\u1eaft c\u1ee7a ch\u00fang ta s\u1ebd nh\u00ecn th\u1ea5y \u00e1nh s\u00e1ng m\u00e0u \u0111\u1ecf. Tuy nhi\u00ean, \u0111\u1ed1i v\u1edbi m\u1ecdi lo\u1ea1i v\u1eadt ch\u1ea5t, ch\u1ec9 c\u00f3 m\u1ed9t l\u01b0\u1ee3ng r\u1ea5t nh\u1ecf \u00e1nh s\u00e1ng b\u1eadt l\u1ea1i t\u1ea1i t\u00f4\u0309ng ca\u0301c b\u00f4\u0323i s\u00f4\u0301 cu\u0309a t\u00e2\u0300n s\u00f4\u0301 chi\u0301nh \u0111\u01b0\u1ee3c ta\u0323o ra. Do v\u1eady, v\u1edbi tia laser m\u00e0u \u0111\u1ecf n\u00e0y, ch\u1ec9 c\u00f3 m\u1ed9t \u00edt \u00e1nh s\u00e1ng xanh b\u1eadt l\u1ea1i tr\u00ean t\u01b0\u1eddng. Ta ch\u1ec9 kh\u00f4ng nh\u00ecn th\u1ea5y n\u00f3 b\u1edfi n\u00f3 qu\u00e1 nh\u1ecf so v\u1edbi to\u00e0n b\u1ed9 l\u01b0\u1ee3ng \u00e1nh s\u00e1ng th\u1ea5y \u0111\u01b0\u1ee3c. C\u00e1c b\u1ed9i s\u1ed1 n\u00e0y g\u1ecdi l\u00e0 h\u1ecda \u00e2m quang h\u1ecdc.<\/p>\n

Th\u00ed nghi\u1ec7m c\u1ee7a nh\u00f3m Hsieh \u0111\u00e3 ch\u1ee9ng minh r\u1eb1ng nh\u1eefng thay \u0111\u1ed5i trong t\u00ednh \u0111\u1ed1i x\u1ee9ng c\u1ee7a m\u1ed9t tinh th\u1ec3 c\u00f3 \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn c\u01b0\u1eddng \u0111\u1ed9 h\u1ecda \u00e2m theo nh\u1eefng c\u00e1ch kh\u00f4ng gi\u1ed1ng nhau. Do s\u1ef1 xu\u1ea5t hi\u1ec7n c\u1ee7a tr\u1eadt t\u1ef1 \u0111a c\u1ef1c l\u00e0m thay \u0111\u1ed5i t\u00ednh \u0111\u1ed1i x\u1ee9ng c\u1ee7a tinh th\u1ec3 theo m\u1ed9t d\u1ea1ng th\u1ee9c c\u1ee5 th\u1ec3 nh\u1ea5t \u0111\u1ecbnh – d\u1ea1ng th\u1ee9c n\u00e0y c\u00f3 th\u1ec3 kh\u00f4ng nh\u1eadn bi\u1ebft \u0111\u01b0\u1ee3c b\u1eb1ng c\u00e1c \u0111\u1ea7u d\u00f2 th\u00f4ng th\u01b0\u1eddng – \u00fd t\u01b0\u1edfng v\u1ec1 ph\u1ea3n \u1ee9ng h\u1ecda \u00e2m quang h\u1ecdc c\u1ee7a m\u1ed9t tinh th\u1ec3 c\u00f3 th\u1ec3 l\u00e0 d\u1ea5u hi\u1ec7u v\u1ec1 tr\u1eadt t\u1ef1 \u0111a c\u1ef1c.<\/p>\n

 <\/p>\n

Trong nghi\u00ean c\u1ee9u g\u1ea7n \u0111\u00e2y nh\u1ea5t c\u1ee7a c\u00e1c nh\u00f3m nghi\u00ean c\u1ee9u kh\u00e1c, d\u1ea5u hi\u1ec7u si\u00eau d\u1eabn \u0111i\u1ec7n trong Sr2IrO4 c\u00f9ng lo\u1ea1i t\u01b0\u01a1ng t\u1ef1 nh\u01b0 d\u1ea5u hi\u1ec7u \u0111\u01b0\u1ee3c t\u00ecm th\u1ea5y trong cuprate v\u00e0 v\u1edbi m\u1ee9c \u0111\u1ed9 t\u01b0\u01a1ng \u0111\u1ed3ng cao gi\u1eefa iridate v\u00e0 cuprate, iridate c\u00f3 th\u1ec3 s\u1ebd gi\u00fap ch\u00fang ta t\u00ecm ra l\u1eddi gi\u1ea3i cho tranh c\u00e3i dai d\u1eb3ng hi\u1ec7n nay v\u1ec1 m\u1ed1i quan h\u1ec7 gi\u1eefa pseudogap v\u00e0 si\u00eau d\u1eabn \u0111i\u1ec7n \u1edf nhi\u1ec7t \u0111\u1ed9 cao.<\/p>\n

C\u00e1c tr\u1eadt t\u1ef1 \u0111a c\u1ef1c c\u00f3 th\u1ec3 t\u1ed3n t\u1ea1i trong nhi\u1ec1u v\u1eadt ch\u1ea5t kh\u00e1c. Sr2IrO4 l\u00e0 v\u1eadt ch\u1ea5t \u0111\u1ea7u ti\u00ean m\u00e0 ch\u00fang ta t\u00ecm hi\u1ec3u v\u00e0 nghi\u00ean c\u1ee9u, do \u0111\u00f3, c\u00e1c tr\u1eadt t\u1ef1 n\u00e0y c\u00f3 th\u1ec3 v\u1eabn c\u00f2n ti\u1ec1m \u1ea9n v\u00e0 ch\u01b0a \u0111\u01b0\u1ee3c ph\u00e1t hi\u1ec7n trong c\u00e1c v\u1eadt ch\u1ea5t kh\u00e1.<\/p>\n

P.K.L (ngu\u1ed3n: Phys.org)<\/em>
\n http:\/\/www.vista.gov.vn<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

Hsieh, GS V\u1eadt l\u00fd h\u1ecdc, ng\u01b0\u1eddi tr\u01b0\u1edbc \u0111\u00e2y \u0111\u00e3 t\u1eebng tham gia m\u1ed9t nh\u00f3m nghi\u00ean c\u1ee9u ph\u00e1t hi\u1ec7n m\u1ed9t tr\u1ea1ng th\u00e1i kh\u00e1c c\u1ee7a v\u1eadt ch\u1ea5t c\u00f3 t\u00ean l\u00e0 ch\u1ea5t c\u00e1ch \u0111i\u1ec7n d\u1ea1ng t\u00f4 p\u00f4, cho bi\u1ebft “Vi\u1ec7c ph\u00e1t hi\u1ec7n ra pha tr\u1ea1ng th\u00e1i n\u00e0y ho\u00e0n to\u00e0n kh\u00f4ng c\u00f3 ch\u1ee7 \u0111\u00edch v\u00e0 kh\u00f4ng d\u1ef1a tr\u00ean b\u1ea5t […]<\/p>\n","protected":false},"author":17,"featured_media":5102,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[47],"tags":[],"class_list":["post-4639","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-tin-tuc"],"_links":{"self":[{"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/posts\/4639","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/users\/17"}],"replies":[{"embeddable":true,"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/comments?post=4639"}],"version-history":[{"count":5,"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/posts\/4639\/revisions"}],"predecessor-version":[{"id":7285,"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/posts\/4639\/revisions\/7285"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/media\/5102"}],"wp:attachment":[{"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/media?parent=4639"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/categories?post=4639"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/tags?post=4639"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}