The surface plasmon polaritons of the topological insulator Bi2Se3 can be excited by using etched grating or grave structures to compensate the wave vector mismatch of the incident photon and plasmon. Here, we demonst...The surface plasmon polaritons of the topological insulator Bi2Se3 can be excited by using etched grating or grave structures to compensate the wave vector mismatch of the incident photon and plasmon. Here, we demonstrate novel gold grating/Bi2Se3 thin film/sapphire hybrid structures, which allow the excitation of surface plasmon polaritons propagating through nondestructive Bi2Se3 thin film with the help of gold diffractive gratings. Utilizing periodic Au surface structures,the momentum can be matched and the normal-incidence infrared reflectance spectra exhibit pronounced dips. When the width of the gold grating W(with a periodicity 2 W) increases from 400 nm to 1500 nm, the resonant frequencies are tuned from about 7000 cm-1 to 2500 cm-1. In contrast to the expected ■ dispersion for both massive and massless fermions,where q ~π/W is the wave vector, we observe a sound-like linear dispersion even at room temperature. This surface plasmon polaritons with linear dispersion are attributed to the unique noninvasive fabrication method and high mobility of topological surface electrons. This novel structure provides a promising application of Dirac plasmonics.展开更多
Nanomagnets are widely used to store information in non-volatile spintronic devices.Spin waves can transfer information with low-power consumption as their propagations are independent of charge transport.However,to d...Nanomagnets are widely used to store information in non-volatile spintronic devices.Spin waves can transfer information with low-power consumption as their propagations are independent of charge transport.However,to dynamically couple two distant nanomagnets via spin waves remains a major challenge for magnonics.Here we experimentally demonstrate coherent coupling of two distant Co nanowires by fast propagating spin waves in an yttrium iron garnet thin film with sub-50 nm wavelengths.Magnons in two nanomagnets are unidirectionally phase-locked with phase shifts controlled by magnon spin torque and spin-wave propagation.The coupled system is finally formulated by an analytical theory in terms of an effective non-Hermitian Hamiltonian.Our results are attractive for analog neuromorphic computing that requires unidirectional information transmission.展开更多
文摘The surface plasmon polaritons of the topological insulator Bi2Se3 can be excited by using etched grating or grave structures to compensate the wave vector mismatch of the incident photon and plasmon. Here, we demonstrate novel gold grating/Bi2Se3 thin film/sapphire hybrid structures, which allow the excitation of surface plasmon polaritons propagating through nondestructive Bi2Se3 thin film with the help of gold diffractive gratings. Utilizing periodic Au surface structures,the momentum can be matched and the normal-incidence infrared reflectance spectra exhibit pronounced dips. When the width of the gold grating W(with a periodicity 2 W) increases from 400 nm to 1500 nm, the resonant frequencies are tuned from about 7000 cm-1 to 2500 cm-1. In contrast to the expected ■ dispersion for both massive and massless fermions,where q ~π/W is the wave vector, we observe a sound-like linear dispersion even at room temperature. This surface plasmon polaritons with linear dispersion are attributed to the unique noninvasive fabrication method and high mobility of topological surface electrons. This novel structure provides a promising application of Dirac plasmonics.
基金We wish to acknowledge the support by the National Key Research and Development Program of China(Nos.2016YFA0300802 and 2017YFA0206200)the National Natural Science Foundation of China(NSFC)(Nos.11674020,12074026 and U1801661)+6 种基金the 111 talent program B16001G.B.was supported by the Netherlands Organization for Scientific Research(NWO)and Japan Society for the Promotion of Science Kakenhi Grants-in-Aid for Scientific Research(No.19H006450)T.Y.was funded through the Emmy Noether Program of Deutsche Forschungsgemeinschaft(SE 2558/2-1)K.X.thanks the National Key Research and Development Program of China(Nos.2017YFA0303304 and 2018YFB0407601)the National Natural Science Foundation of China(Nos.61774017 and 11734004)K.S.was supported by the Fundamental Research Funds for the Central Universities(No.2018EYT02)M.Z.W.were supported by the US National Science Foundation(No.EFMA-1641989).
文摘Nanomagnets are widely used to store information in non-volatile spintronic devices.Spin waves can transfer information with low-power consumption as their propagations are independent of charge transport.However,to dynamically couple two distant nanomagnets via spin waves remains a major challenge for magnonics.Here we experimentally demonstrate coherent coupling of two distant Co nanowires by fast propagating spin waves in an yttrium iron garnet thin film with sub-50 nm wavelengths.Magnons in two nanomagnets are unidirectionally phase-locked with phase shifts controlled by magnon spin torque and spin-wave propagation.The coupled system is finally formulated by an analytical theory in terms of an effective non-Hermitian Hamiltonian.Our results are attractive for analog neuromorphic computing that requires unidirectional information transmission.
