Paramagnetic LaCoSi,a ternary intermetallic electride,consists of CoSi blocks separated by two layers of La atoms.Its structure is similar to that of the widely studied 111 system of iron-based superconductors.Utilizi...Paramagnetic LaCoSi,a ternary intermetallic electride,consists of CoSi blocks separated by two layers of La atoms.Its structure is similar to that of the widely studied 111 system of iron-based superconductors.Utilizing angle-resolved photoemission spectroscopy and first-principles calculations,we demonstrate the existence of linear bands and flat bands mainly originating from the orbitals of Co 3d states near the Fermi energy.The anomalous scattering rate of the linear bands varies linearly with the binding energy.The flat band above the Fermi energy indicated by the calculations could be modulated by substitutions and pressure to induce new ordered quantum phases,such as magnetism and superconductivity.Our findings reveal flat-band physics in electrides.展开更多
We systematically investigated the tunable dynamic characteristics of a broadband surface plasmon polariton(SPP) wave on a silicon-graded grating structure in the range of 10–40 THz with the aid of single-layer graph...We systematically investigated the tunable dynamic characteristics of a broadband surface plasmon polariton(SPP) wave on a silicon-graded grating structure in the range of 10–40 THz with the aid of single-layer graphene.The theoretical and numerical simulated results demonstrate that the SPPs at different frequencies within a broadband range can be trapped at different positions on the graphene surface, which can be used as a broadband spectrometer and optical switch. Meanwhile, the group velocity of the SPPs can be modulated to be several hundred times smaller than light velocity in vacuum. Based on the theoretical analyses, we have predicted the trapping positions and corresponding group velocities of the SPP waves with different frequencies. By appropriately tuning the gate voltages, the trapped SPP waves can be released to propagate along the surface of graphene or out of the graded grating zone. Thus, we have also investigated the switching characteristics of the slow light system, where the optical switching can be controlled as an "off" or "on" mode by actively adjusting the gate voltage. The slow light system offers advantages, including broadband operation, ultracompact footprint, and tunable ability simultaneously, which holds great promise for applications in optical switches.展开更多
基金supported by the National Key R&D Program of China(Grant No.2022YFB3608000)the National Natural Science Foundation of China(NSFC)(Grant Nos.12222413 and 12074041)+5 种基金the Natural Science Foundation of Shanghai(Grant Nos.23ZR1482200 and 22ZR1473300)the Funding of Ningbo Yongjiang Talent Program,the Natural Science Foundation of Ningbo,Ningbo University(No.LJ2024003)the Postdoctoral Fellowship Program of CPSF(Grant No.GZC20240951)the Natural Science Foundation of Shandong Province(Grant Nos.ZR2021QA031,ZR2023MA068,and ZR2024QA213)the Qingdao Postdoctoral Project Funding(No.QDBSH20240102115)the Fundamental Research Funds for the Central Universities(Grant No.2243300003).
文摘Paramagnetic LaCoSi,a ternary intermetallic electride,consists of CoSi blocks separated by two layers of La atoms.Its structure is similar to that of the widely studied 111 system of iron-based superconductors.Utilizing angle-resolved photoemission spectroscopy and first-principles calculations,we demonstrate the existence of linear bands and flat bands mainly originating from the orbitals of Co 3d states near the Fermi energy.The anomalous scattering rate of the linear bands varies linearly with the binding energy.The flat band above the Fermi energy indicated by the calculations could be modulated by substitutions and pressure to induce new ordered quantum phases,such as magnetism and superconductivity.Our findings reveal flat-band physics in electrides.
基金Fundamental Research Funds for the Central Universities(JD2017JGPY0005)National Natural Science Foundation of China(NSFC)(61775050)
文摘We systematically investigated the tunable dynamic characteristics of a broadband surface plasmon polariton(SPP) wave on a silicon-graded grating structure in the range of 10–40 THz with the aid of single-layer graphene.The theoretical and numerical simulated results demonstrate that the SPPs at different frequencies within a broadband range can be trapped at different positions on the graphene surface, which can be used as a broadband spectrometer and optical switch. Meanwhile, the group velocity of the SPPs can be modulated to be several hundred times smaller than light velocity in vacuum. Based on the theoretical analyses, we have predicted the trapping positions and corresponding group velocities of the SPP waves with different frequencies. By appropriately tuning the gate voltages, the trapped SPP waves can be released to propagate along the surface of graphene or out of the graded grating zone. Thus, we have also investigated the switching characteristics of the slow light system, where the optical switching can be controlled as an "off" or "on" mode by actively adjusting the gate voltage. The slow light system offers advantages, including broadband operation, ultracompact footprint, and tunable ability simultaneously, which holds great promise for applications in optical switches.
