We study theoretically the exciton Bose–Einstein condensation and exciton vortices in a two-dimensional(2 D)perovskite(PEA)2 Pb I4 monolayer.Combining the first-principles calculations and the Keldysh model,the excit...We study theoretically the exciton Bose–Einstein condensation and exciton vortices in a two-dimensional(2 D)perovskite(PEA)2 Pb I4 monolayer.Combining the first-principles calculations and the Keldysh model,the exciton binding energy of in a(PEA)2 Pb I4 monolayer can approach hundreds of me V,which make it possible to observe the excitonic effect at room temperature.Due to the large exciton binding energy,and hence the high density of excitons,we find that the critical temperature of the exciton condensation could approach the liquid nitrogen regime.In the presence of perpendicular electric fields,the dipole-dipole interaction between excitons is found to drive the condensed excitons confined in(PEA)2 Pb I4 monolayer flakes into patterned vortices,as the evolution time of vortex patterns is comparable to the exciton lifetime.展开更多
Based on the Gross–Pitaevskii equation,we theoretically investigate exciton Bose–Einstein condensation(BEC)in transition metal dichalcogenide monolayers(TMDC-MLs)under in-plane magnetic fields.We observe that the in...Based on the Gross–Pitaevskii equation,we theoretically investigate exciton Bose–Einstein condensation(BEC)in transition metal dichalcogenide monolayers(TMDC-MLs)under in-plane magnetic fields.We observe that the in-plane magnetic fields exert a strong influence on the exciton BEC wave functions in TMDC-MLs because of the mixing of the bright and dark exciton states via Zeeman effect.This leads to the brightening of the dark exciton BEC states.The competition between the dipole–dipole interactions caused by the long-range Coulomb interaction and the Zeeman effect induced by the in-plane magnetic fields can effectively regulate dark exciton BEC states.Our findings emphasize the utility of TMD-MLs as platforms for investigating collective phenomenon involving excited states.展开更多
基金Supported by the National Key R&D Programme of China(Grant Nos.2017YFA0303400 and 2016YFE0110000)the National Natural Science Foundation of China(Grant Nos.11574303 and 11504366)+1 种基金the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2018148)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB28000000)。
文摘We study theoretically the exciton Bose–Einstein condensation and exciton vortices in a two-dimensional(2 D)perovskite(PEA)2 Pb I4 monolayer.Combining the first-principles calculations and the Keldysh model,the exciton binding energy of in a(PEA)2 Pb I4 monolayer can approach hundreds of me V,which make it possible to observe the excitonic effect at room temperature.Due to the large exciton binding energy,and hence the high density of excitons,we find that the critical temperature of the exciton condensation could approach the liquid nitrogen regime.In the presence of perpendicular electric fields,the dipole-dipole interaction between excitons is found to drive the condensed excitons confined in(PEA)2 Pb I4 monolayer flakes into patterned vortices,as the evolution time of vortex patterns is comparable to the exciton lifetime.
基金supported by the National Natural Science Foundation of China(Grant Nos.92265203 and 11974340)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB0460000,XDB28000000,and XDPB22)+1 种基金the Chinese Academy of Sciences(Grant No.QYZDJSSW-SYS001)the National Key R&D Program of China(Grant No.2018YFA0306101).
文摘Based on the Gross–Pitaevskii equation,we theoretically investigate exciton Bose–Einstein condensation(BEC)in transition metal dichalcogenide monolayers(TMDC-MLs)under in-plane magnetic fields.We observe that the in-plane magnetic fields exert a strong influence on the exciton BEC wave functions in TMDC-MLs because of the mixing of the bright and dark exciton states via Zeeman effect.This leads to the brightening of the dark exciton BEC states.The competition between the dipole–dipole interactions caused by the long-range Coulomb interaction and the Zeeman effect induced by the in-plane magnetic fields can effectively regulate dark exciton BEC states.Our findings emphasize the utility of TMD-MLs as platforms for investigating collective phenomenon involving excited states.
