Cov kws tshawb fawb ntawm University of Basel thiab ETH hauv Zurich tau ua tiav hauv kev hloov pauv polarity ntawm ferromagnet tshwj xeeb uas siv lub laser beam. Nyob rau hauv lub neej yav tom ntej, txoj kev no yuav siv tau los tsim adaptable electronic circuits nrog lub teeb.
Nyob rau hauv ib lub ferromagnet, kev sib xyaw ua ke yog ua haujlwm. Nyob rau hauv thiaj li yuav ib tug compass koob mus rau sab qaum teb los yog ib tug fridge hlau nplaum rau lo rau lub fridge qhov rooj, countless electrons spin nyob rau hauv lawv, txhua tus tsuas yog tsim ib tug me me magnetic teb, tag nrho cov yuav tsum tau kab nyob rau hauv tib txoj kev. Qhov no tshwm sim los ntawm kev sib cuam tshuam ntawm cov kev sib tw, uas yuav tsum muaj zog tshaj qhov tsis sib haum xeeb thermal txav hauv cov ferromagnet. Yog tias qhov kub ntawm cov khoom qis dua qhov tseem ceeb, nws yuav dhau los ua ferromagnetic.
Hloov pauv, txhawm rau hloov lub polarity ntawm ferromagnet, ib qho feem ntau yuav tsum tau ua ntej ua kom sov nws saum nws qhov kub thiab txias. Cov electron spines tuaj yeem hloov kho lawv tus kheej, thiab tom qab txias, qhov chaw sib nqus ntawm ferromagnet nws thiaj li taw tes rau lwm qhov kev taw qhia.
Ib pab neeg tshawb fawb coj los ntawm Prof. Dr. Tomasz Smoleński ntawm University of Basel thiab Prof. Dr. Ataç Imamoğlu ntawm ETH hauv Zurich tam sim no tau tswj hwm kom coj cov kev hloov pauv no - kev taw qhia siv lub teeb tsuas yog - yam tsis muaj cua sov. Lawv luam tawm lawv cov txiaj ntsig hauvXwm.
Kev sib tham thiab topology
"Dab tsi zoo siab ntawm peb txoj haujlwm yog tias peb muab peb lub ntsiab lus tseem ceeb hauv kev niaj hnub condensed teeb meem physics hauv ib qho kev sim: muaj kev sib cuam tshuam ntawm electrons, topology thiab dynamical tswj," Imamoğlu hais.
Txhawm rau ua tiav qhov no, cov kws tshawb fawb tau siv cov khoom tshwj xeeb uas muaj ob lub wafer -cov txheej nyias nyias ntawm cov organic semiconductor molybdenum ditelluride, uas yog me ntsis twisted ntawm ib leeg.
Hauv cov ntaub ntawv zoo li no, yog li -hu ua topological xeev tuaj yeem tsim. Hais lus yooj yim, lub xeev topological tuaj yeem ua tus cwj pwm raws li qhov lawv zoo li: pob (tsis muaj qhov) lossis donut (ib lub qhov). Qhov tseem ceeb, lub pob tsis tuaj yeem hloov mus rau hauv ib qho khoom qab zib los ntawm qhov yooj yim deformation, uas txhais tau hais tias cov xeev topological yog qhov tseeb thiab tsis muaj tseeb.
Hauv kev sim tshiab co- saib xyuas los ntawm Smoleński thiab Imamoğlu, cov khoom siv hluav taws xob tuaj yeem hloov kho ntawm lub xeev topological uas yog insulating thiab metallic xeev uas tab tom ua. Remarkably, kev sib cuam tshuam ua rau cov electron spin nyob rau hauv ob lub xeev los ua kom sib npaug rau ib leeg, tig cov khoom rau hauv ferromagnet.
"Peb qhov txiaj ntsig tseem ceeb yog tias peb tuaj yeem siv lub laser mem tes los hloov cov kev taw qhia ntawm kev sib tw," hais Olivier Huber, Ph.D. tub ntxhais kawm ntawm ETH, uas tau ua qhov kev sim ua ke nrog nws cov npoj yaig Kilian Kuhlbrodt thiab Tomasz Smoleński. Ob peb xyoos dhau los, qhov no twb tau ua tiav rau ib qho hluav taws xob, tab sis tam sim no qhov "hloov" lossis kev hloov pauv ntawm cov polarity ntawm tag nrho cov ferromagnet tau ua tiav.
Smoleński hais tias "Qhov kev hloov pauv no tau mus tas li thiab, ntxiv rau, qhov topology cuam tshuam rau kev hloov pauv hloov pauv," Smoleński hais.
Tshawb nrhiav qhov tseeb hauv kev tshawb fawb, thev naus laus zis, thiab qhov chaw nrog dhau100,000 subscribersuas tso siab rau Phys.org rau kev nkag siab txhua hnub. Sau npe rau peb tsab ntawv xov xwm pub dawb thiab tau txais kev hloov tshiab ntawm kev ua tiav, kev tsim kho tshiab, thiab kev tshawb fawb uas tseem ceeb-txhua hnub los yog txhua lub lim tiam.
Sau npe
Dynamical tswj ntawm ferromagnet
Nyob rau hauv txoj kev no, lub laser mem tes kuj tuaj yeem siv los kos cov kab ciam teb tshiab, sab hauv uas lub xeev topological ferromagnetic nyob. Qhov no tuaj yeem ua tau ntau zaus, thiaj li muaj peev xwm tswj tau lub zog ntawm topological thiab ferromagnetic zog.
Txhawm rau qhia tias cov ferromagnet me me, uas tsuas yog ob peb micrometers loj, tau hloov pauv nws cov polarity, cov kws tshawb fawb tau ntsuas qhov kev xav ntawm ib qho thib ob, ntau lub zog laser beam. Qhov kev xav no qhia txog kev taw qhia ntawm cov electron spin.
Smoleński hais tias "Nyob rau yav tom ntej, peb yuav tuaj yeem siv peb txoj hauv kev los sau qhov tsis txaus ntseeg thiab hloov pauv hloov pauv hloov pauv ntawm lub nti," Smoleński hais. Txoj hauv kev no tuaj yeem siv los tsim cov interferometers me me, uas tsis tshua muaj hluav taws xob me me tuaj yeem ntsuas tau.
