Ua holomua ma ke aʻo ʻana i ka neʻe ultrafast o Weil quasiparticles i mālama ʻia enā lasers
I nā makahiki i hala iho nei, ua lilo ka noiʻi theoretical a me ka hoʻokolohua e pili ana i ka topological quantum states a me ka topological quantum material i kumuhana wela ma ke kula o ka condensed matter physics. Ma ke ʻano he manaʻo hou o ka hoʻokaʻawale ʻana o ka mea, ʻo ke ʻano topological, e like me ka symmetry, he manaʻo koʻikoʻi i ka physics mea condensed. ʻO ka ʻike hohonu o ka topology e pili ana i nā pilikia maʻamau i loko o ka physics mea condensed, e like me ke ʻano uila uila onā pae kuantum, ka hoʻololi ʻana o ka pae quantum a me ka hauʻoli o nā mea immobilized he nui i nā pae quantum. Ma nā mea topological, ʻo ka hoʻohui ʻana ma waena o nā pae he nui o ke kūʻokoʻa, e like me nā electrons, phonons a me spin, ke kuleana koʻikoʻi i ka hoʻomaopopo ʻana a me ka hoʻoponopono ʻana i nā waiwai waiwai. Hiki ke ho'ohana 'ia ka 'olu'olu māmā no ka 'ike 'ana ma waena o nā pilina like 'ole a me ka ho'oponopono 'ana i ka moku'āina o ka mea, a laila hiki ke loa'a ka 'ike e pili ana i ka waiwai kino o ka mea, ka ho'ololi 'ana o ka pae, a me nā moku'āina quantum hou. I kēia manawa, ua lilo ka pilina ma waena o nā ʻano macroscopic o nā mea topological i alakaʻi ʻia e ka māla māmā a me kā lākou microscopic atomic structure a me nā waiwai uila i lilo i pahuhopu noiʻi.
ʻO ke ʻano pane photoelectric o nā mea topological pili loa i kona ʻano uila uila microscopic. No nā semi-metala topological, ʻo ka hoʻoulu ʻana o ka mea lawe ma kahi kokoke i ke kuʻekuʻe ʻana o ka band e ʻike nui ʻia i nā ʻano hana nalu o ka ʻōnaehana. ʻO ke aʻo ʻana i nā hanana optical nonlinear i nā semi-metala topological hiki ke kōkua iā mākou e hoʻomaopopo maikaʻi i nā waiwai kino o nā ʻano hauʻoli o ka ʻōnaehana, a ua manaʻo ʻia e hiki ke hoʻohana ʻia kēia mau hopena i ka hana ʻananā mea ʻike makaa me ka hoʻolālā ʻana o nā cell solar, e hāʻawi ana i nā noi kūpono i ka wā e hiki mai ana. No ka laʻana, i ka Weyl semi-metal, ʻo ka lawe ʻana i kahi photon o ke kukui polarized circularly polarized e hoʻohuli i ka wili, a i mea e hoʻokō ai i ka mālama ʻana i ka manawa angular, e puʻunaue like ʻia ka hoʻoulu electron ma nā ʻaoʻao ʻelua o ka cone Weyl. ʻO ke kuhikuhi o ka hoʻolaha ʻana o ka māmā circularly polarized, i kapa ʻia ʻo ka lula koho chiral (Figure 1).
Hoʻohana maʻamau ka noiʻi ʻana o nā ʻano optical nonlinear o nā mea topological i ke ʻano o ka hoʻohui ʻana i ka helu ʻana o nā waiwai o ka honua a me ka nānā ʻana i ka symmetry. Eia nō naʻe, he mau hemahema kēia ʻano: ʻaʻole i loaʻa ka ʻike maoli o nā mea lawe hauʻoli i ka manawa kūpono a me ka lewa maoli, a ʻaʻole hiki ke hoʻokumu i kahi hoʻohālikelike pololei me ke ʻano ʻike hoʻokolohua i hoʻoholo ʻia i ka manawa. ʻAʻole hiki ke noʻonoʻo ʻia ka hui ʻana ma waena o nā electron-phonons a me photon-phonons. A he mea koʻikoʻi kēia no ka hiki ʻana o kekahi mau hoʻololi. Eia kekahi, ʻaʻole hiki i kēia loiloi theoretical e pili ana i ka perturbation theory ke hana i nā kaʻina hana kino ma lalo o ke kahua kukui ikaika. ʻO ka simulation molecular dynamics (TDDFT-MD) pili i ka manawa e pili ana i nā kumu mua hiki ke hoʻonā i nā pilikia i luna.
I kēia mau lā, ma lalo o ke alakaʻi ʻana a ka mea noiʻi ʻo Meng Sheng, ka mea noiʻi postdoctoral Guan Mengxue a me ka haumāna kaukaʻo Wang En o ka SF10 Group o ka State Key Laboratory of Surface Physics o ka Institute of Physics o ka Chinese Academy of Sciences/Beijing National Research Center for Concentrated Matter. Physics, ma ka laulima pū me Professor Sun Jiatao o ka Beijing Institute of Technology, ua hoʻohana lākou i ka polokalamu TDAP hoʻohauʻoli mokuʻāina i hoʻomohala ʻia. ʻO nā hiʻohiʻona pane o ka quastiparticle excitation i ka laser ultrafast ma ke ʻano lua o Weyl semi-metal WTe2 e noiʻi ʻia.
Ua hōʻike ʻia ka koho ʻana o nā mea lawe kokoke i ke kiko Weyl e hoʻoholo ʻia e ka atomic orbital symmetry a me ka lula koho transition, he ʻokoʻa ia mai ka lula koho spin maʻamau no ka excitation chiral, a hiki ke hoʻomalu ʻia kona ala hauʻoli ma ka hoʻololi ʻana i ke kuhikuhi polarization. o ka malamalama polarized linearly a me ka ikehu photon (FIG. 2).
ʻO ka asymmetric excitation o nā mea lawe e hoʻoulu i nā photocurrents ma nā ʻaoʻao like ʻole i ka lewa maoli, e pili ana i ke kuhikuhi a me ka symmetry o ka slip interlayer o ka ʻōnaehana. No ka mea, ʻo nā waiwai topological o WTe2, e like me ka helu o nā helu Weyl a me ke kiʻekiʻe o ka hoʻokaʻawale ʻana i ka manawa momentum, ua hilinaʻi nui ʻia i ka symmetry o ka ʻōnaehana (Figure 3), ʻo ka asymmetric excitation o nā mea lawe e lawe mai i nā ʻano like ʻole o Weyl. quastiparticles i loko o ka manawa momentum a me nā loli like i nā waiwai topological o ka ʻōnaehana. No laila, hāʻawi ka haʻawina i kahi kiʻikuhi maʻalahi no ka hoʻololi ʻana o ka pae phototopological (Figure 4).
Hōʻike nā hopena e nānā pono ʻia ka chirality o ka hoʻoulu ʻana o ka mea lawe kokoke i ka lae Weyl, a e nānā ʻia nā waiwai orbital atomic o ka hana hawewe. Ua like nā hopena o nā mea ʻelua akā ʻokoʻa ka mīkini, e hāʻawi ana i kahi kumu kumu no ka wehewehe ʻana i ka singularity o nā helu Weyl. Eia kekahi, hiki i ke ʻano helu helu i lawe ʻia i loko o kēia haʻawina hiki ke hoʻomaopopo hohonu i nā pilina paʻakikī a me nā ʻano dynamical ma nā pae atomic a me ka uila i kahi manawa wikiwiki loa, e hōʻike i kā lākou microphysical mechanical, a ua manaʻo ʻia he mea hana ikaika no ka noiʻi e hiki mai ana. nā mea ʻike ʻole linear i nā mea topological.
Aia nā hopena ma ka puke pai Nature Communications. Kākoʻo ʻia ka hana noiʻi e ka National Key Research and Development Plan, ka National Natural Science Foundation a me ka Strategic Pilot Project (Category B) o ka Chinese Academy of Science.
FIG.1.a. ʻO ka lula koho chirality no nā kiko Weyl me ka hōʻailona chirality maikaʻi (χ=+1) ma lalo o ke kukui polarized circularly; ʻO ka hoʻoulu ʻana ma muli o ke ʻano orbital symmetry ma ka lae Weyl o b. χ=+1 i ke kukui polarized pūnaewele
FIG. 2. Kiʻikuhi hoʻolālā atomika o a, Td-WTe2; b. ʻO ka hui pū ma kahi kokoke i ka ʻili Fermi; (c) ʻO ka hui pū ʻana a me nā haʻawina pili o nā orbital atomic i puʻunaue ʻia ma nā laina likemmetric kiʻekiʻe ma ka ʻāina ʻo Brillouin, ʻo nā pua (1) a me (2) e hōʻike ana i ka hauʻoli kokoke a mamao paha mai nā kiko Weyl, kēlā me kēia; d. ʻO ka hoʻonui ʻia ʻana o ka hui pū ma ke ala Gamma-X
FIG.3.ab: ʻO ka neʻe ʻana o ka neʻe ʻana o ka ʻaoʻao polarization māmā linearly polarized ma ka A-axis a me B-axis o ke aniani, a ua hōʻike ʻia ke ʻano o ka neʻe ʻana; C. Hoʻohālikelike ma waena o ka simulation theoretical a me ka nānā hoʻokolohua; de: Hoʻololi like ʻole o ka ʻōnaehana a me ke kūlana, ka helu a me ke degere o ka hoʻokaʻawale ʻana o nā kiko Weyl ʻelua kokoke loa i ka mokulele kz=0.
FIG. 4. ʻO ka hoʻololi ʻana o ka pae Phototopological i Td-WTe2 no ka ikehu photon māmā laina polarized (?) ω) a me ka ʻaoʻao polarization (θ) ke kiʻikuhi pae hilinaʻi.
Ka manawa hoʻouna: Sep-25-2023