Cryogenic low-noise amplifiers for measurements with superconducting detectors

• Ilya L. Novikov,
• Boris I. Ivanov,
• Dmitri V. Ponomarev and
• Aleksey G. Vostretsov

Beilstein J. Nanotechnol. 2020, 11, 1316–1320, doi:10.3762/bjnano.11.115

• ; Introduction Currently, superconducting detectors are the most sensitive devices in the electromagnetic field and find wide application in radioastronomy and quantum electronics. Sensors based on superconductors can detect microwaves close to the single-photon limit [1]. Most of such sensors are based on

Proximity effect in [Nb(1.5 nm)/Fe(x)]₁₀/Nb(50 nm) superconductor/ferromagnet heterostructures

• Yury Khaydukov,
• Sabine Pütter,
• Laura Guasco,
• Roman Morari,
• Gideok Kim,
• Thomas Keller,
• Anatolie Sidorenko and
• Bernhard Keimer

Beilstein J. Nanotechnol. 2020, 11, 1254–1263, doi:10.3762/bjnano.11.109

• following work of the same group [39] the modification of IEC by hydrogen uptake was reported. An advantage of niobium as N spacer is that it is the superconducting material with the highest bulk TC = 9.3 K among all elemental superconductors. However, the thickest Nb spacer layer where AP alignment is

• superconductors: . From Hc2(0) we can estimate the superconducting correlation length ξS = 12 nm. We note that 2D superconductivity was reported earlier for various structures with Nb layer thicknesses of 100 nm or less [5][33][35][36][41]. Discussion In this work we studied the structural, magnetic and

3D superconducting hollow nanowires with tailored diameters grown by focused He⁺ beam direct writing

• Rosa Córdoba,
• Alfonso Ibarra,
• Dominique Mailly,
• Isabel Guillamón,
• Hermann Suderow and
• José María De Teresa

Beilstein J. Nanotechnol. 2020, 11, 1198–1206, doi:10.3762/bjnano.11.104

• nano-antennas and sensors, based on 3D superconducting architectures. Keywords: electron tomography; focused ion beam induced deposition (FIBID); helium ion microscope; magneto-transport measurements; nano-superconductors; tungsten carbide (WC); Introduction Superconductors are dissipationless

• for quantum computation. The behavior of nanosized superconductors as one-dimensional quantum oscillators [1], Josephson junction arrays [2], electronic transport devices [3][4][5][6][7], very small-scale devices [8][9], micrometer-scale coolers [10], or thermal and spin sensors [11][12] has been

• studied in detail. Nowadays, research on manufacturing highly energy-efficient three-dimensional (3D) structures [13] is critical for the development of future electronics. However, when approaching the nanometer-scale, the number of works on real 3D nano-superconductors [14][15][16][17][18][19] decreases

Nonadiabatic superconductivity in a Li-intercalated hexagonal boron nitride bilayer

• Kamila A. Szewczyk,
• Izabela A. Domagalska,
• Artur P. Durajski and
• Radosław Szczęśniak

Beilstein J. Nanotechnol. 2020, 11, 1178–1189, doi:10.3762/bjnano.11.102

• superconductors under high magnetic fields [74]. Unfortunately, due to enormous mathematical difficulties, their full self-consistent solutions are still unknown (Δn,k and Zn,k). Also, Freericks’ equations have been recently successfully used to analyze the superconducting state with high critical temperature

Microwave photon detection by an Al Josephson junction

• Leonid S. Revin,
• Andrey L. Pankratov,
• Anna V. Gordeeva,
• Anton A. Yablokov,
• Igor V. Rakut,
• Victor O. Zbrozhek and
• Leonid S. Kuzmin

Beilstein J. Nanotechnol. 2020, 11, 960–965, doi:10.3762/bjnano.11.80

• layered high-temperature superconductors [27]. The significance of this effect depends on the ratio of thermal fluctuations kBT, the damping parameter α and the Josephson energy EJ. Here we will consider a small tunnel junction with the thermal noise intensity of γ = kBT/EJ ≥ 2 × 10−2 and α > 0.1, and

A Josephson junction based on a highly disordered superconductor/low-resistivity normal metal bilayer

• Pavel M. Marychev and
• Denis Yu. Vodolazov

Beilstein J. Nanotechnol. 2020, 11, 858–865, doi:10.3762/bjnano.11.71

• Josephson junction resembles Josephson junctions based on a S’-S-S’system composed of two superconductors S and S’ having DS′ ≫ DS and the same thicknesses dS = dS′ [17][20][21]. A Josephson junction based on this quasi 1D system has a single-valued CPR, which approaches a sinusoidal shape with increasing

Epitaxial growth and superconducting properties of thin-film PdFe/VN and VN/PdFe bilayers on MgO(001) substrates

• Wael M. Mohammed,
• Igor V. Yanilkin,
• Amir I. Gumarov,
• Airat G. Kiiamov,
• Roman V. Yusupov and
• Lenar R. Tagirov

Beilstein J. Nanotechnol. 2020, 11, 807–813, doi:10.3762/bjnano.11.65

• temperatures. Also, there is a room to optimize the superconducting parameters of the VN film towards an increase in Tc by about 1 K [43][44]. In our opinion, the results hint at a possible use of heteroepitaxial combinations of nitrides as superconductors and palladium-rich Pd1−xFex alloys as weak tunable

High dynamic resistance elements based on a Josephson junction array

• Konstantin Yu. Arutyunov and
• Janne S. Lehtinen

Beilstein J. Nanotechnol. 2020, 11, 417–420, doi:10.3762/bjnano.11.32

• superconductors. The basics of this approach were developed in the late 1980s, resulting in rapid single flux quantum (RSFQ) logic [2]. Since that time the concept has continued to develop. However, the corresponding systems so far have not developed into mass market commercial products, being limited solely to

Anomalous current–voltage characteristics of SFIFS Josephson junctions with weak ferromagnetic interlayers

• Tairzhan Karabassov,
• Anastasia V. Guravova,
• Aleksei Yu. Kuzin,
• Elena A. Kazakova,
• Shiro Kawabata,
• Boris G. Lvov and
• Andrey S. Vasenko

Beilstein J. Nanotechnol. 2020, 11, 252–262, doi:10.3762/bjnano.11.19

• superconductivity and ferromagnetism are two competing antagonistic orders. In superconductors (S) electrons form Cooper pairs with opposite spins and momenta, while in ferromagnetic metals (F) electron spins tend to align in parallel. Nevertheless, it is possible to combine S and F layers in one hybrid structure

Nitrogen-vacancy centers in diamond for nanoscale magnetic resonance imaging applications

• Alberto Boretti,
• Lorenzo Rosa,
• Jonathan Blackledge and
• Stefania Castelletto

Beilstein J. Nanotechnol. 2019, 10, 2128–2151, doi:10.3762/bjnano.10.207

• to the study of static and dynamic magnetic textures and current distributions. As an example, NV magnetometry is used to probe magnets and superconductors, correlated-electron physics, as well as to explore the current distribution in low-dimensional materials. In addition, the study of static

• measurement of the lower (first) critical field of three different superconductors, high-Tc cuprate YBa2Cu3O7−δ (YBCO), and iron-based superconductors is performed, as the lower critical field is a fundamental parameter to characterize a type-II superconductor. Sample cooling to a target temperature below Tc

• is done under zero magnetic field, and then a small magnetic field is delivered while recording ODMR signals in various positions on the sample to evaluate homogeneity. From the ODMR splitting at various temperatures, the magnetization is obtained. The transition temperature to superconductors is

Materials nanoarchitectonics at two-dimensional liquid interfaces

• Katsuhiko Ariga,
• Michio Matsumoto,
• Taizo Mori and
• Lok Kumar Shrestha

Beilstein J. Nanotechnol. 2019, 10, 1559–1587, doi:10.3762/bjnano.10.153

• nanosheets. At 90% carbon tetrachloride content, the average pore size became ca. 400 nm. These integrated two-dimensional structures would be nanoarchitectonics pieces for the fabrication of sensitive sensors, organic solar cells, and miniaturized organic superconductors. As a functional development of two

Periodic Co/Nb pseudo spin valve for cryogenic memory

• Nikolay Klenov,
• Yury Khaydukov,
• Sergey Bakurskiy,
• Roman Morari,
• Igor Soloviev,
• Vladimir Boian,
• Thomas Keller,
• Mikhail Kupriyanov,
• Anatoli Sidorenko and
• Bernhard Keimer

Beilstein J. Nanotechnol. 2019, 10, 833–839, doi:10.3762/bjnano.10.83

• memory applications. As a basis for a weak link we propose to use a periodic structure composed of ferromagnetic (F) layers spaced by thin superconductors (s). Our calculations based on the Usadel equations show that switching from parallel (P) to antiparallel (AP) alignment of neighboring F layers can

• )/Co(2.5 nm)/Nb(8 nm)]6/Co(1.5 nm)/Nb(25 nm) structure. We took niobium as a superconducting material since it has the highest TC = 9.25 K among all elemental superconductors and forms stable structures with cobalt [19][26][27][28][29][30]. The thickness of the Nb-spacer was chosen to be close to ξS

Transport signatures of an Andreev molecule in a quantum dot–superconductor–quantum dot setup

• Zoltán Scherübl,
• András Pályi and
• Szabolcs Csonka

Beilstein J. Nanotechnol. 2019, 10, 363–378, doi:10.3762/bjnano.10.36

• Group, Budapest University of Technology and Economics, 1111 Budapest, Hungary 10.3762/bjnano.10.36 Abstract Hybrid devices combining quantum dots with superconductors are important building blocks of conventional and topological quantum-information experiments. A requirement for the success of such

• experiments and applications. Keywords: Andreev bound state; crossed Andreev reflection; elastic co-tunneling; quantum dot; Introduction Superconducting hybrid nanodevices provide a promising platform for quantum architectures. While superconductors (SCs) allow for a spatially extended coherent state

Recent highlights in nanoscale and mesoscale friction

• Andrea Vanossi,
• Dirk Dietzel,
• Andre Schirmeisen,
• Ernst Meyer,
• Rémy Pawlak,
• Thilo Glatzel,
• Marcin Kisiel,
• Shigeki Kawai and
• Nicola Manini

Beilstein J. Nanotechnol. 2018, 9, 1995–2014, doi:10.3762/bjnano.9.190

• locally disturbing the charge density waves [188] (Figure 7). At a certain threshold, the CDW shows a phase slip, which then leads to dissipation. Another example where non-contact friction can be influenced by external parameters are the measurements of superconductors across the critical temperature

A zero-dimensional topologically nontrivial state in a superconducting quantum dot

• Pasquale Marra,
• Alessandro Braggio and
• Roberta Citro

Beilstein J. Nanotechnol. 2018, 9, 1705–1714, doi:10.3762/bjnano.9.162

• temperatures. Keywords: Josephson effect; Josephson junctions; quantum dots; superconducting quantum dots; topological states; topological superconductors; Introduction Since the discovery of the quantum Hall effect [1][2] and the theoretical prediction of Majorana bound states in triplet superconductors [3

• ., in a system with discrete energy spectrum. A very important class of topological states of matter are topological superconductors: These materials support Majorana zero-energy modes at the edges of the system [11][12][13], which have been proposed as the building block of topological quantum devices

• ]. Moreover, topological superconductors exhibit very distinct features in their transport properties and in particular in their Josephson current [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49]. In a recent work [50], we have studied the short-size limit of a

Josephson effect in junctions of conventional and topological superconductors

• Alex Zazunov,
• Albert Iks,
• Miguel Alvarado,
• Alfredo Levy Yeyati and
• Reinhold Egger

Beilstein J. Nanotechnol. 2018, 9, 1659–1676, doi:10.3762/bjnano.9.158

• , Universidad Autónoma de Madrid, E-28049 Madrid, Spain 10.3762/bjnano.9.158 Abstract We present a theoretical analysis of the equilibrium Josephson current-phase relation in hybrid devices made of conventional s-wave spin-singlet superconductors (S) and topological superconductor (TS) wires featuring Majorana

• superconductors (TSs) is being vigorously explored at present. After Kitaev [1] showed that a one-dimensional (1D) spinless fermionic lattice model with nearest-neighbor p-wave pairing (‘Kitaev chain’) features a topologically nontrivial phase with Majorana bound states (MBSs) at open boundaries, references [2][3

• , we naturally extend previous works on Josephson junctions with a magnetic impurity between two conventional superconductors, as well as other works on Josephson junctions between topological and non-topological superconductors but without a magnetic impurity. In the simplest description, Josephson

Spatial Rabi oscillations between Majorana bound states and quantum dots

• Jun-Hui Zheng,
• Dao-Xin Yao and
• Zhi Wang

Beilstein J. Nanotechnol. 2018, 9, 1527–1535, doi:10.3762/bjnano.9.143

• splitting between two Majorana bound states. Keywords: Andreev bound state; Majorana bound state; nonlocal quantum correlation; quantum dot; spatial Rabi oscillation; Introduction Majorana bound states are exotic non-Abelian quasiparticles in topological superconductors [1][2][3][4][5][6][7][8][9][10][11

• ][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. The study of Majorana bound states has attracted tremendous interest recently because they constitute topological parity qubits. These qubits are defined by the degenerate ground states of topological superconductors, and therefore are

• , we take the even total parity, and get a 4 × 4 matrix, Now let us look at the quantum dots coupling with two Andreev bound states at the end of the nanowire island. Since Andreev bound states are eigenstates of superconductors, there are, in principle, four energy levels in the entire system. The

Robust topological phase in proximitized core–shell nanowires coupled to multiple superconductors

• Tudor D. Stanescu,
• Anna Sitek and
• Andrei Manolescu

Beilstein J. Nanotechnol. 2018, 9, 1512–1526, doi:10.3762/bjnano.9.142

• Science and Engineering, Reykjavik University, Menntavegur 1, IS-101 Reykjavik, Iceland 10.3762/bjnano.9.142 Abstract We consider core–shell nanowires with prismatic geometry contacted with two or more superconductors in the presence of a magnetic field applied parallel to the wire. In this geometry, the

• system in the presence of non-vanishing transverse potentials and finite relative phases between the parent superconductors. We show that having finite relative phases strongly enhances the stability of the induced topological superconductivity over a significant range of chemical potentials and reduces

• systems is motivated, in part, by the perspective of using them as a platform for fault-tolerant topological quantum computation [1][2][3][4]. Several practical realizations of “synthetic” topological superconductors that host zero-energy Majorana modes have been proposed in the past few years, the most

Interplay between pairing and correlations in spin-polarized bound states

• Szczepan Głodzik,
• Aksel Kobiałka,
• Anna Gorczyca-Goraj,
• Andrzej Ptok,
• Grzegorz Górski,
• Maciej M. Maśka and
• Tadeusz Domański

Beilstein J. Nanotechnol. 2018, 9, 1370–1380, doi:10.3762/bjnano.9.129

• near to the singlet–doublet phase transition. Keywords: bound states in superconductors; Majorana quasiparticles; subgap Kondo effect; Introduction Magnetism is usually detrimental to superconductivity because it breaks the Cooper pairs (at the critical field strength Hc2). There are, however, a few

Disorder-induced suppression of the zero-bias conductance peak splitting in topological superconducting nanowires

• Jun-Tong Ren,
• Hai-Feng Lü,
• Sha-Sha Ke,
• Yong Guo and
• Huai-Wu Zhang

Beilstein J. Nanotechnol. 2018, 9, 1358–1369, doi:10.3762/bjnano.9.128

• -matter systems, including p-wave superconductors [10][11], topological insulator-superconductor hybrid structures [12][13], artificially engineered Kitaev chains [14][15], semiconductor-superconductor hybrid nanowire systems [16][17][18][19][20][21]. Very recently, the one-dimensional Majorana mode

• several experiments since 2012 [23][24][25][26][27][28][29][30]. As an important signature of MBSs in the semiconductor nanowires which are proximity-coupled to s-wave superconductors, the zero-bias conductance peak has been observed in the tunneling spectra in the presence of a finite magnetic field [23

Andreev spectrum and supercurrents in nanowire-based SNS junctions containing Majorana bound states

• Jorge Cayao,
• Annica M. Black-Schaffer,
• Elsa Prada and
• Ramón Aguado

Beilstein J. Nanotechnol. 2018, 9, 1339–1357, doi:10.3762/bjnano.9.127

• states (MBSs) in engineered topological superconductors. We perform a systematic numerical study of the low-energy Andreev spectrum and supercurrents in short and long superconductor–normal–superconductor junctions made of nanowires with strong Rashba spin–orbit coupling, where an external Zeeman field

• on top of two s-wave superconductors (S’) with pairing potentials ΔS′ and subjected to an external magnetic field (denoted by the black arrow). Superconducting correlations are induced into the nanowire through the proximity effect. Bottom: Left and right regions of the nanowire become

Formation mechanisms of boron oxide films fabricated by large-area electron beam-induced deposition of trimethyl borate

• Aiden A. Martin and
• Philip J. Depond

Beilstein J. Nanotechnol. 2018, 9, 1282–1287, doi:10.3762/bjnano.9.120

• -containing materials are diverse and include high-energy laser fusion targets [1], superconductors [2], X-ray optics [3], microelectromechanical systems [4], and neutron detectors [5]. All these alluring applications are, however, overshadowed by fabrication challenges at the microscale arising from

Proximity effect in a two-dimensional electron gas coupled to a thin superconducting layer

• Christopher Reeg,
• Daniel Loss and
• Jelena Klinovaja

Beilstein J. Nanotechnol. 2018, 9, 1263–1271, doi:10.3762/bjnano.9.118

• . Keywords: Majorana fermions; mesoscopic physics; proximity effect; quantum computing; topological superconductivity; Introduction Topological superconductors host zero-energy Majorana bound states at their edges that are highly sought for applications in topological quantum computing [1][2][3]. The two

Circular dichroism of chiral Majorana states

• Javier Osca and
• Llorenç Serra

Beilstein J. Nanotechnol. 2018, 9, 1194–1199, doi:10.3762/bjnano.9.110

• for px ± ipy fields and, obviously, also a vanishing CD. Model We use the model of [17] for a quantum-anomalous Hall (3D) thin film in contact with two different superconductors. This model represents the device as two surfaces with a certain interaction between them, with Majorana states being

Inverse proximity effect in semiconductor Majorana nanowires

• Alexander A. Kopasov,
• Ivan M. Khaymovich and
• Alexander S. Mel'nikov

Beilstein J. Nanotechnol. 2018, 9, 1184–1193, doi:10.3762/bjnano.9.109

• indirectly superconducting region is affected by effective Zeeman field through tunneling. The presence of several solutions for Tc is typical for the standard paramagnetic effect in superconductors and usually this behavior results in the FFLO instability of the homogeneous solution for the gap function [32