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Emergent interlayer nodal superfluidity of a dipolar Fermi gas in bilayer optical lattices
摘要： Understanding the interplay between magnetism and superconductivity is one of the central issues in high-temperature superconductors. The recent experimental implementation of cold gases with highly tunable anisotropic interaction, especially in magnetic dipolar atoms or polar molecules, opens up a new thrust on exploring this interesting phenomenon. Here we report a mechanism to drive the interplay between magnetism and superfluidity through engineering the spatially anisotropic interaction via considering loading pseudospin-1/2 dipolar Fermi atoms in bilayer optical lattices. Surprisingly, we find that the weak interlayer interaction can lead to the coexistence of superfluidity and antiferromagnetism at low temperatures for the half filling case. It is distinguished from the usual scheme by doping an antiferromagnetic Mott insulating parent to access high-Tc superconductivity, where at half filling there is no coexistence of superconductivity and magnetism at low temperatures due to the absence of the superconductivity. Furthermore, the interlayer superfluid possesses an unexpected nodal structure, which is reminiscent of the nodal high-Tc superconductivity but differs in origin.
关键词： antiferromagnetism,bilayer optical lattices,dipolar Fermi atoms,superfluidity,interlayer interaction,superconductivity,magnetism,nodal structure
更新于2025-09-09 09:28:46
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Nanowire-Based Josephson Junctions
摘要： The combination of superconductivity and surface states in Dirac semimetal can produce a 4π-periodic supercurrent in a Josephson junction configuration, which can be revealed by the missing of odd Shapiro steps (especially the n ? 1 step). However, the suppression of the n ? 1 step is also anticipated in the high-power oscillatory regime of the ordinary 2π-periodic Josephson effect, which is irrelevant to the 4π-periodic supercurrent. Here, in order to identify the origin of the suppressed n ? 1 step, we perform the measurements of radio frequency irradiation on Nb–Dirac semimetal Cd3As2 nanowire–Nb junctions with continuous power dependence at various frequencies. Besides the n ? 1 step suppression, we uncover a residual supercurrent of first node at the n ? 0 step, which provides a direct and predominant signature of the 4π-periodic supercurrent. Furthermore, by tuning the gate voltage, we can modulate the surface and bulk state contribution and the visibility of the n ? 1 step. Our results provide deep insights to explore the topological superconductivity in Dirac semimetals.
关键词： surface states,Cd3As2 nanowire,topological superconductivity,4π-periodic supercurrent,Josephson junctions
更新于2025-09-09 09:28:46
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Charge-stripe crystal phase in an insulating cuprate
摘要： High-temperature (high-Tc) superconductivity in cuprates arises from carrier doping of an antiferromagnetic Mott insulator. This carrier doping leads to the formation of electronic liquid-crystal phases. The insulating charge-stripe crystal phase is predicted to form when a small density of holes is doped into the charge-transfer insulator state, but this phase is yet to be observed experimentally. Here, we use surface annealing to extend the accessible doping range in Bi-based cuprates and realize the lightly doped charge-transfer insulating state of the cuprate Bi2Sr2CaCu2O8+x. In this insulating state with a charge transfer gap on the order of ~1 eV, our spectroscopic imaging scanning tunnelling microscopy measurements provide strong evidence for a unidirectional charge-stripe order with a commensurate 4a0 period along the Cu–O–Cu bond. Notably, this insulating charge-stripe crystal phase develops before the onset of the pseudogap and formation of the Fermi surface. Our work provides fresh insight into the microscopic origin of electronic inhomogeneity in high-Tc cuprates.
关键词： spectroscopic imaging scanning tunnelling microscopy,electronic inhomogeneity,cuprates,charge-stripe crystal phase,high-temperature superconductivity
更新于2025-09-09 09:28:46
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Reactivity studies and structural properties of Al on compound semiconductor surfaces
摘要： The authors studied the structural properties of Al on III-V semiconductors (InAs, GaAs, and InGaAs) with the aim of creating smooth and abrupt interfaces. Growth conditions, such as the residual As content and the presence of intermediate layers, affect the structural properties of the Al and the underlying semiconductor. The authors find that an ultrathin layer of AlAs on (001) InAs drastically reduces the interface reaction and improves the epitaxial growth of Al. No such layer is necessary for interface reaction mitigation for Al deposited onto InGaAs or GaAs. The crystal orientation of Al planes grown on (001) InAs is [110], but is [111] on InGaAs or GaAs. The authors discuss the significance of the results for realization of structures for proximity superconductivity.
关键词： GaAs,InAs,Al,epitaxial growth,proximity superconductivity,InGaAs,interface reaction,III-V semiconductors
更新于2025-09-04 15:30:14
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/epitaxial graphene van der Waals heterostructure
摘要： We report on direct observation of interface superconductivity in single-unit-cell SnSe2 films grown on graphitized SiC(0001) substrate. The tunneling spectrum in the superconducting state reveals a rather conventional character with a fully gapped order parameter. The occurrence of superconductivity is further confirmed by the observation of vortices under external magnetic field. Through interface engineering, we unravel the mechanism of superconductivity that originates from a two-dimensional electron gas formed at the interface of SnSe2 and graphene. Our finding opens up novel strategies to hunt for and understand interface superconductivity based on van der Waals heterostructures.
关键词： two-dimensional electron gas,interface superconductivity,van der Waals heterostructure,SnSe2,graphene
更新于2025-09-04 15:30:14