Manipulating emergent quantum phenomena is a key issue for understanding the underlying physics and contributing to possible applications.Here we study the evolution of insulating ground states of Ta_(2)Pu_(3)Te_(5) a...Manipulating emergent quantum phenomena is a key issue for understanding the underlying physics and contributing to possible applications.Here we study the evolution of insulating ground states of Ta_(2)Pu_(3)Te_(5) and Ta_(2)Ni_(3)Te_(5) under in-situ surface potassium deposition via angle-resolved photoemission spectroscopy.Our results confirm the excitonic insulator character of Ta_(2)d_(3)Te_(5).Upon surface doping,the size of its global gap decreases obviously.After a deposition time of more than 7 min,the potassium atoms induce a metal-insulator phase transition and make the system recover to a normal state.In contrast,our results show that the isostructural compound Ta_(2)Ni_(3)Te_(5) is a conventional insulator.The size of its global gap decreases upon surface doping,but persists positive throughout the doping process.Our results not only confirm the excitonic origin of the band gap in Ta_(2)Pd_(3)Te_(5),but also offer an effective method for designing functional quantum devices in the future.展开更多
The low-temperature (T = 2 K) exciton-polariton luminescence (EPL) spectra in the vicinity of the exciton-resonance frequency An=1 for CdS-type crystals have been theoretically and experimentally investigated with all...The low-temperature (T = 2 K) exciton-polariton luminescence (EPL) spectra in the vicinity of the exciton-resonance frequency An=1 for CdS-type crystals have been theoretically and experimentally investigated with allowance for the mechanical exciton decay . The results of the numerical calculations of the partial and interference contributions of the bulk and radiative surface spectral modes to the EPL in the geometry of additional s- and p-polarized waves emitted into vacuum are analyzed. It is shown that the contributions of purely longitudinal excitons and their interference with polaritons of the upper dispersion branch near the longitudinal frequency ωL to the EPL are small (∼10% - 30%);nevertheless, they must be taken into account to obtain quantitative agreement with experimental data. Specifically these contributions are responsible for the formation of an additional line (along with the fundamental AT line) in the case of oblique incidence of radiation.展开更多
We report an experimental investigation of the influence of surface charges on the emission polarization properties of single CdSe/CdS dot-in-rods(DRs),which is important for their polarization-based practical applica...We report an experimental investigation of the influence of surface charges on the emission polarization properties of single CdSe/CdS dot-in-rods(DRs),which is important for their polarization-based practical applications.By covering the single DRs with N-type semiconductor indium tin oxide(ITO)nanoparticles,the surface of single DRs is charged by ITO through interracial electron transfer.This is confirmed by the experimental observations of the reduced photoluminescence intensities and lifetimes as well as the suppressing blinking.It is found that the full width at half maximum of histogram of polarization degrees of the single DRs is broadened from 0.24(on glass)to 0.41(in ITO).In order to explain the exprimental results,the band-edge exciton fine structure of single DRs is calculated by taking into account the sample parameters,the emission polarization,and the surface charges.The calculation results show that the level ordering of the emitting states determines the polarization degrees tending to increase or decrease under the influence of surface electrons.The surface electrons can induce an increase in the spacing between the emitting levels to change the populations and thus change the polarization degrees.In addition,different numbers of surface electrons may randomly distribute on the long CdSe/CdS rods,leading to the heterogeneous influences on the single DRs causing the broadening of polarization degrees also.展开更多
Strong coupling between plasmons and multiple different exciton states(MESs)enables the creation of multiple hybrid polariton states under ambient conditions.These hybrid states possess unique optical properties diffe...Strong coupling between plasmons and multiple different exciton states(MESs)enables the creation of multiple hybrid polariton states under ambient conditions.These hybrid states possess unique optical properties different from those of their separate identities,making them ideal candidates for exploiting room-temperature multimode hybridization and multiqubit operation.In this study,we revealed the static spectral response properties of plasmon-MES strong coupling via a fully quantum mechanics approach.These theoretical predictions were experimentally demonstrated in plasmonic nanocavities containing two and three different exciton species.Additionally,the dynamical absorption processes of such strong coupling systems were investigated,and results indicated that the damping of the hybrid polariton states induced by the strong coupling could be markedly modulated by the acoustic oscillations from the plasmonic nanocavities.Our findings contribute a theoretical approach for accurately describing the plasmon-MES interactions and a platform for developing the high-speed active plasmonic devices based on multiqubit strong coupling.展开更多
基金Project supported by the Ministry of Science and Technology of China (Grant No. 2022YFA1403800)the National Natural Science Foundation of China (Grant Nos. U2032204,12188101, and U22A6005)+2 种基金the Chinese Academy of Sciences (Grant No. XDB33000000)the Synergetic Extreme Condition User Facility (SECUF)the Center for Materials Genome。
文摘Manipulating emergent quantum phenomena is a key issue for understanding the underlying physics and contributing to possible applications.Here we study the evolution of insulating ground states of Ta_(2)Pu_(3)Te_(5) and Ta_(2)Ni_(3)Te_(5) under in-situ surface potassium deposition via angle-resolved photoemission spectroscopy.Our results confirm the excitonic insulator character of Ta_(2)d_(3)Te_(5).Upon surface doping,the size of its global gap decreases obviously.After a deposition time of more than 7 min,the potassium atoms induce a metal-insulator phase transition and make the system recover to a normal state.In contrast,our results show that the isostructural compound Ta_(2)Ni_(3)Te_(5) is a conventional insulator.The size of its global gap decreases upon surface doping,but persists positive throughout the doping process.Our results not only confirm the excitonic origin of the band gap in Ta_(2)Pd_(3)Te_(5),but also offer an effective method for designing functional quantum devices in the future.
文摘The low-temperature (T = 2 K) exciton-polariton luminescence (EPL) spectra in the vicinity of the exciton-resonance frequency An=1 for CdS-type crystals have been theoretically and experimentally investigated with allowance for the mechanical exciton decay . The results of the numerical calculations of the partial and interference contributions of the bulk and radiative surface spectral modes to the EPL in the geometry of additional s- and p-polarized waves emitted into vacuum are analyzed. It is shown that the contributions of purely longitudinal excitons and their interference with polaritons of the upper dispersion branch near the longitudinal frequency ωL to the EPL are small (∼10% - 30%);nevertheless, they must be taken into account to obtain quantitative agreement with experimental data. Specifically these contributions are responsible for the formation of an additional line (along with the fundamental AT line) in the case of oblique incidence of radiation.
基金The project was sponsored by the National Key Research and Development Program of China(Grant No.2017YFA0304203)the National Natural Science Foundation of China(Grant Nos.61527824,61675119,11434007,61875109,and 61605104)PCSIRT(Grant No.IRT.17R70),1331KSC and 111 project(Grant No.D18001).
文摘We report an experimental investigation of the influence of surface charges on the emission polarization properties of single CdSe/CdS dot-in-rods(DRs),which is important for their polarization-based practical applications.By covering the single DRs with N-type semiconductor indium tin oxide(ITO)nanoparticles,the surface of single DRs is charged by ITO through interracial electron transfer.This is confirmed by the experimental observations of the reduced photoluminescence intensities and lifetimes as well as the suppressing blinking.It is found that the full width at half maximum of histogram of polarization degrees of the single DRs is broadened from 0.24(on glass)to 0.41(in ITO).In order to explain the exprimental results,the band-edge exciton fine structure of single DRs is calculated by taking into account the sample parameters,the emission polarization,and the surface charges.The calculation results show that the level ordering of the emitting states determines the polarization degrees tending to increase or decrease under the influence of surface electrons.The surface electrons can induce an increase in the spacing between the emitting levels to change the populations and thus change the polarization degrees.In addition,different numbers of surface electrons may randomly distribute on the long CdSe/CdS rods,leading to the heterogeneous influences on the single DRs causing the broadening of polarization degrees also.
基金supported by the National Natural Science Foundation of China(Grant Nos.11874438,22105063,61905066,61805070,1200410122103024)+1 种基金Natural Science Foundation of Guangdong(Grant Nos.2021A1515010050,and 2018A030313722)Guangdong Polytechnic Normal University Talent Introduction Project Foundation of China(Grant No.XY2019022)。
文摘Strong coupling between plasmons and multiple different exciton states(MESs)enables the creation of multiple hybrid polariton states under ambient conditions.These hybrid states possess unique optical properties different from those of their separate identities,making them ideal candidates for exploiting room-temperature multimode hybridization and multiqubit operation.In this study,we revealed the static spectral response properties of plasmon-MES strong coupling via a fully quantum mechanics approach.These theoretical predictions were experimentally demonstrated in plasmonic nanocavities containing two and three different exciton species.Additionally,the dynamical absorption processes of such strong coupling systems were investigated,and results indicated that the damping of the hybrid polariton states induced by the strong coupling could be markedly modulated by the acoustic oscillations from the plasmonic nanocavities.Our findings contribute a theoretical approach for accurately describing the plasmon-MES interactions and a platform for developing the high-speed active plasmonic devices based on multiqubit strong coupling.
