Topological Dirac semimetals(DSMs) present a kind of topologically nontrivial quantum state of matter, which has massless Dirac fermions in the bulk and topologically protected states on certain surfaces. In supercond...Topological Dirac semimetals(DSMs) present a kind of topologically nontrivial quantum state of matter, which has massless Dirac fermions in the bulk and topologically protected states on certain surfaces. In superconducting DSMs, the effects of their nontrivial topology on superconducting pairing could realize topological superconductivity in the bulk or on the surface. As superconducting pairing takes place at the Fermi level E_F, to make the effects possible, the Dirac points should lie in the vicinity of E_F so that the topological electronic states can participate in the superconducting paring. Here,we show using angle-resolved photoelectron spectroscopy that in a series of(Ir_(1-x)Pt_x)Te_2 compounds, the type-Ⅱ Dirac points reside around E_F in the superconducting region, in which the bulk superconductivity has a maximum T_c of ～ 3 K.The realization of the coexistence of bulk superconductivity and low-energy Dirac fermions in(Ir_(1-x)Pt_x)Te_2 paves the way for studying the effects of the nontrivial topology in DSMs on the superconducting state.展开更多
Nowadays,inertial confinement fusion(ICF)research related to noncontact positioning and transport of free-standing cryogenic targets is playing an increasingly important role in this field.The operational principle be...Nowadays,inertial confinement fusion(ICF)research related to noncontact positioning and transport of free-standing cryogenic targets is playing an increasingly important role in this field.The operational principle behind these technologies is the magnetic acceleration of the levitating target carrier(or sabot)made from Type-Ⅱ,high-temperature superconductors(HTSCs).The physics of interaction among levitation,guidance and propulsion systems is based on a quantum levitation of high-pinning HTSCs in the mutually normal magnetic fields.This paper discusses current target delivery strategies and future perspectives to create different permanent magnet guideway(PMG)systems for ICF target transport with levitation.In particular,several PMG building options for optimizing both suspension and levitation of ICF targets using an HTSC-sabot will be analyzed.Credible solutions have been demonstrated for both linear and round PMGs,including the ones with a cyclotron acceleration process to realize high-running velocities of the HTSCsabot for a limited magnetic track.Focusing on physics,we describe in detail the main aspects of the PMG building and the results obtained from computations and proof of principle experiments.High-pinning HTSC magnetic levitation promises a stable and self-controlled levitation to accelerate the ICF targets placed in the HTSC-sabots up to the required injection velocities of 200 m/s and beyond.展开更多
基金supported by the Ministry of Science and Technology of China(Grant Nos.2016YFA0300600,2016YFA0401000,2016YFA0302400,and2017YFA0302901)the National Natural Science Foundation of China(Grant Nos.11622435,U1832202,and 11674369)+1 种基金the Chinese Academy of Sciences(Grant Nos.QYZDB-SSW-SLH043,XDB07000000,and XDPB08-1)the Beijing Municipal Science and Technology Commission,China(Grant No.Z171100002017018)
文摘Topological Dirac semimetals(DSMs) present a kind of topologically nontrivial quantum state of matter, which has massless Dirac fermions in the bulk and topologically protected states on certain surfaces. In superconducting DSMs, the effects of their nontrivial topology on superconducting pairing could realize topological superconductivity in the bulk or on the surface. As superconducting pairing takes place at the Fermi level E_F, to make the effects possible, the Dirac points should lie in the vicinity of E_F so that the topological electronic states can participate in the superconducting paring. Here,we show using angle-resolved photoelectron spectroscopy that in a series of(Ir_(1-x)Pt_x)Te_2 compounds, the type-Ⅱ Dirac points reside around E_F in the superconducting region, in which the bulk superconductivity has a maximum T_c of ～ 3 K.The realization of the coexistence of bulk superconductivity and low-energy Dirac fermions in(Ir_(1-x)Pt_x)Te_2 paves the way for studying the effects of the nontrivial topology in DSMs on the superconducting state.
基金the IAEA within project No.24154,‘Modeling of the Optics Degradation under Ionizing Radiation and Mass Fabrication of Low Aspect-Ratio Targets for a Repetition-Rate IFE Facility’the framework of the LPI State Task and under the program of the Presidium of the Russian Academy of Sciences。
文摘Nowadays,inertial confinement fusion(ICF)research related to noncontact positioning and transport of free-standing cryogenic targets is playing an increasingly important role in this field.The operational principle behind these technologies is the magnetic acceleration of the levitating target carrier(or sabot)made from Type-Ⅱ,high-temperature superconductors(HTSCs).The physics of interaction among levitation,guidance and propulsion systems is based on a quantum levitation of high-pinning HTSCs in the mutually normal magnetic fields.This paper discusses current target delivery strategies and future perspectives to create different permanent magnet guideway(PMG)systems for ICF target transport with levitation.In particular,several PMG building options for optimizing both suspension and levitation of ICF targets using an HTSC-sabot will be analyzed.Credible solutions have been demonstrated for both linear and round PMGs,including the ones with a cyclotron acceleration process to realize high-running velocities of the HTSCsabot for a limited magnetic track.Focusing on physics,we describe in detail the main aspects of the PMG building and the results obtained from computations and proof of principle experiments.High-pinning HTSC magnetic levitation promises a stable and self-controlled levitation to accelerate the ICF targets placed in the HTSC-sabots up to the required injection velocities of 200 m/s and beyond.
