| 1. |
- Baghdadi, Reza, 1984, et al.
(författare)
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Josephson effect through YBa2Cu3 O7-δ /Au-encapsulated nanogaps
- 2017
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Ingår i: Physical Review B. - 2469-9969 .- 2469-9950. ; 95:17
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Tidskriftsartikel (refereegranskat)abstract
- We successfully fabricated and studied planar superconductor-normal-superconductor (SNS) Josephson junctions made of YBa2Cu3O7-? (YBCO) high-TC superconductor (S) and Au normal metal (N). The crucial step in fabrication was done by using a Pt/Au bilayer encapsulation of the patterned YBCO nanogap. This procedure preserves the YBCO nanogap from the degradation due to the contact with resists, water, and chemicals involved in further processing for hybrid devices. The junctions exhibit Fraunhofer-like modulation patterns and Shapiro steps when they are irradiated by a rf field. Furthermore, we analyzed the IC(T) characteristics of our hybrid junctions employing a SINI?S (superconductor-insulator-normal conductor-insulator-superconductor) model.
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| 2. |
- Kunakova, Gunta, 1987, et al.
(författare)
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Space charge limited current mechanism in Bi2S3 nanowires
- 2016
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 119:11
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Tidskriftsartikel (refereegranskat)abstract
- We report on the charge transport properties of individual Bi2S3 nanowires grown within the pores of anodized aluminum oxide templates. The mean pore diameter was 80 nm. Space charge limited current is the dominating conduction mechanism at temperatures below 160 K. Characteristic parameters of nanowires, such as trap concentration and trap characteristic energy, were estimated from current-voltage characteristics at several temperatures.
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| 3. |
- Salvato, Matteo, et al.
(författare)
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Nanometric Moire Stripes on the Surface of Bi2Se3 Topological Insulator
- 2022
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-086X .- 1936-0851. ; 16:9, s. 13860-13868
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Tidskriftsartikel (refereegranskat)abstract
- Mismatch between adjacent atomic layers in low-dimensional materials, generating moire patterns, has recently emerged as a suitable method to tune electronic properties by inducing strong electron correlations and generating novel phenomena. Beyond graphene, van der Waals structures such as three-dimensional (3D) topological insulators (TIs) appear as ideal candidates for the study of these phenomena due to the weak coupling between layers. Here we discover and investigate the origin of 1D moire stripes on the surface of Bi2Se3 TI thin films and nanobelts. Scanning tunneling microscopy and high-resolution transmission electron microscopy reveal a unidirectional strained top layer, in the range 14-25%, with respect to the relaxed bulk structure, which cannot be ascribed to the mismatch with the substrate lattice but rather to strain induced by a specific growth mechanism. The 1D stripes are characterized by a spatial modulation of the local density of states, which is strongly enhanced compared to the bulk system. Density functional theory calculations confirm the experimental findings, showing that the TI surface Dirac cone is preserved in the 1D moire stripes, as expected from the topology, though with a heavily renormalized Fermi velocity that also changes between the top and valley of the stripes. The strongly enhanced density of surface states in the TI 1D moire superstructure can be instrumental in promoting strong correlations in the topological surface states, which can be responsible for surface magnetism and topological superconductivity.
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