On‐Demand Local Modification of High‐Tc Superconductivity in Few Unit‐Cell Thick Bi2Sr2CaCu2O8+δ

Ghosh, Sanat; Vaidya, Jaykumar; Datta, Sayantan; Pandeya, Ram Prakash; Jangade, Digambar; Kulkarni, R.G.; Maiti, Kalobaran; Thamizhavel, A.; Deshmukh, Mandar M.

doi:10.1002/adma.202002220

Cited by 14 publications

(8 citation statements)

References 28 publications

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“…As shown in our earlier study [14], we selectively deposit Cr on the surface of freshly cleaved few unit cells thick flake of BSCCO, thereby making underneath superconductor insulating, schematically shown in figure 1(b). Following this strategy, we deposit two Cr lines on exfoliated thin BSCCO with a gap in between the Cr lines to define the nanowire, as shown in figure 1(c).…”

Section: Methodsmentioning

confidence: 99%

Nanowire bolometer using a 2D high-temperature superconductor

Ghosh¹,

Jangade²,

Deshmukh³

2022

Nanotechnology

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Superconducting nanowires are very important due to their applications ranging from quantum technology to astronomy. In this work, we implement a non-invasive process to fabricate nanowires of high-Tc superconductor Bi2Sr2CaCu2O8+δ (BSCCO). We demonstrate that our nanowires can be used as bolometers in the visible range with very high responsivity of 9.7 × 103 V/W. Interestingly, in a long (30 μm) nanowire of 9 nm thickness and 700 nm width, we observe bias current dependent localized spots of maximum photovoltage. Moreover, the scalability of the bolometer responsivity with the normal state resistance of the nanowire could allow further performance improvement by increasing the nanowire length in a meander geometry. We observe phase slip events in nanowires with small cross-sections (12 nm thick, 300 nm wide, and 3μm long) at low temperatures. Our study presents a scalable method for realizing sensitive bolometers working near the liquid-nitrogen temperature.

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Section: Methodsmentioning

confidence: 99%

Nanowire bolometer using a 2D high-temperature superconductor

Ghosh¹,

Jangade²,

Deshmukh³

2022

Nanotechnology

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“…These double evaporations aim to avoid deposition of the Cr directly onto the BSCCO, which would result in an insulating behavior of the underlying region, as Cr could capture oxygen atoms from the flakes. [ 33 ] We found that the contact resistance obtained from the deposition of Cr right onto the sample by performing a single evaporation (Au/Cr) was of the order of 1 kΩ, which is ten times higher than the resistance of the contact obtained by the two‐steps evaporation protocol. Figure a,b shows the closeup optical images of two representative devices, one without encapsulation on top of the junction and the other with encapsulation, respectively.…”

Section: Fabricationmentioning

confidence: 98%

Encapsulating High‐Temperature Superconducting Twisted van der Waals Heterostructures Blocks Detrimental Effects of Disorder

et al. 2023

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High‐temperature cuprate superconductors based van der Waals (vdW) heterostructures hold high technological promise. One of the obstacles hindering their progress is the detrimental effect of disorder on the properties of the vdW‐devices‐based Josephson junctions (JJs). Here, a new method of fabricating twisted vdW heterostructures made of Bi2Sr2CuCa2O8+δ, crucially improving the JJ characteristics and pushing them up to those of the intrinsic JJs in bulk samples, is reported. The method combines cryogenic stacking using a solvent‐free stencil mask technique and covering the interface by insulating hexagonal boron nitride crystals. Despite the high‐vacuum condition down to 10−6 mbar in the evaporation chamber, the interface appears to be protected from water molecules during the in situ metal deposition only when fully encapsulated. Comparing the current–voltage curves of encapsulated and unencapsulated interfaces, it is revealed that the encapsulated interfaces’ characteristics are crucially improved, so that the corresponding JJs demonstrate high critical currents and sharpness of the superconducting transition comparable to those of the intrinsic JJs. Finally, it is shown that the encapsulated heterostructures are more stable over time.

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“…This two steps evaporation aims at avoiding the deposition of the Cr directly onto the flakes since Cr oxidizes by ripping off oxygen molecules from the BSCCO. This undesired chemical reaction would lead to an insulating behavior of the region underlying the contact layer, strongly degrading the superconducting properties of the entire device [39]. Using this protocol, we obtain the high-quality electrical contact with the areal resistance smaller than 50 kΩµm 2 , an order of magnitude lower than the contact resistance resulting from a single evaporation (Au/Cr) on BSCCO under our conditions.…”

Section: Fabrication Of High-quality Josephson Junctionsmentioning

confidence: 99%

Twisted cuprate van der Waals heterostructures with controlled Josephson coupling

Martini¹,

Lee²,

Confalone³

et al. 2023

Preprint

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Twisted van der Waals (vdW) heterostructures offer a unique platform for engineering the efficient Josephson coupling between cuprate thin crystals harboring the nodal superconducting order parameter. Preparing vdW heterostructures-based Josephson junction comprising stacked cuprates requires maintaining an ordered interface with preserved surface superconductivity. Here, we report the preparation of the Josephson junction out of the stacked Bi2Sr2CuCa2O 8+d crystals using the cryogenic dry transfer technique and encapsulating the junction with an insulating layer, that protects the interface during the electrical contacts evaporation at the 1 × 10 −6 mbar base pressure. We find that the Josephson critical current Ic has a maximum at low twist angles, comparable to that of the bulk intrinsic Josephson junctions, and is reduced by two orders of magnitude at twist angles close to 45°. The reduction of Ic occurs due to a mismatch between superconducting d-wave order parameters, which suppresses the direct Cooper pair tunneling.

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On‐Demand Local Modification of High‐T_c Superconductivity in Few Unit‐Cell Thick Bi₂Sr₂CaCu₂O_8+δ

Cited by 14 publications

References 28 publications

Nanowire bolometer using a 2D high-temperature superconductor

Nanowire bolometer using a 2D high-temperature superconductor

Encapsulating High‐Temperature Superconducting Twisted van der Waals Heterostructures Blocks Detrimental Effects of Disorder

Twisted cuprate van der Waals heterostructures with controlled Josephson coupling

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