Article
Chemistry, Physical
Leonid Morgun, Svetoslav Kuzmichev, Igor Morozov, Alena Degtyarenko, Andrey Sadakov, Andrey Shilov, Ilya Zhuvagin, Yevgeny Rakhmanov, Tatiana Kuzmicheva
Summary: A comprehensive study of the superconducting properties of underdoped NaFe0.979Co0.021As single crystals is presented, using a combination of upper critical field measurements and incoherent multiple Andreev reflection effect (IMARE) spectroscopy. The study reveals the temperature dependence of the Hc2(T) and the characteristics of the superconducting order parameters.
Article
Chemistry, Physical
Maxim M. Korshunov, Svetoslav A. Kuzmichev, Tatiana E. Kuzmicheva
Summary: We directly observed temperature-dependent spin excitons in the Andreev spectra of iron-based superconductors. Our observation, combined with other experimental evidence, confirms the extended s-wave order parameter symmetry and indirectly supports the spin-fluctuation mechanism of Cooper pairing.
Article
Physics, Applied
Sedighe Salimian, Matteo Carrega, Isha Verma, Valentina Zannier, Michal P. Nowak, Fabio Beltram, Lucia Sorba, Stefan Heun
Summary: High-quality InSb nanoflags, as a versatile III-V semiconductor material, show great potential in advanced quantum technologies, especially in realizing topological superconducting states. Fabrication of ballistic Josephson-junction devices based on InSb nanoflags allows for tunable proximity-induced supercurrent, indicating a promising platform for future quantum applications.
APPLIED PHYSICS LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Soumyadip Halder, Mona Garg, Nikhlesh Singh Mehta, Anamika Kumari, Rajesh Sharma, Tanmoy Das, Suvankar Chakraverty, Goutam Sheet
Summary: The conducting interfaces of perovskite oxides are important for various quantum phenomena and potential applications in superconducting nano-electronic devices. We discovered two-dimensional superconductivity below Tc approximately 250 mK at the interfaces between the Mott-insulator LaVO3 and the band-insulator SrTiO3. Our findings suggest the existence of an unconventional order parameter, supported by spectroscopic measurements of Andreev reflection.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
Review
Physics, Condensed Matter
Sandeep Howlader, Goutam Sheet
Summary: This article discusses a novel way of inducing superconductivity in non-superconducting topological materials by creating a mesoscopic interface with a non-superconducting metal tip on the material. This "tip-induced superconducting (TISC)" phase has been observed in many topological materials. As the TISC phase only emerges in a confined region under a mesoscopic point contact, traditional bulk tools for characterizing superconductivity are not applicable for detecting or confirming such a phase.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Article
Materials Science, Multidisciplinary
Ritesh Kumar, Goutam Sheet
Summary: The paper discusses transport properties in N/S point contacts in the ballistic regime, emphasizing the impact of Andreev reflection in superconductors. It is found that even in simple and conventional superconductors, a variety of spectral features may appear in the conductance spectra depending on the shape and size of the contact.
Article
Multidisciplinary Sciences
Svetoslav Kuzmichev, Tatiana Kuzmicheva, Igor Morozov, Alexander Boltalin, Andrey Shilov
Summary: The structure of the superconducting order parameter in LiFeAs is studied using incoherent multiple Andreev reflections effect (IMARE) spectroscopy. SnS junctions show the presence of at least three bulk superconducting order parameters in LiFeAs, and we discuss their symmetry.
SN APPLIED SCIENCES
(2022)
Article
Physics, Applied
Sandeep Howlader, Nikhlesh Singh Mehta, M. M. Sharma, V. P. S. Awana, Goutam Sheet
Summary: Binary compounds of SnT family, particularly SnAs, exhibit novel properties like superconductivity and topologically protected states, which have attracted significant interest. Previous studies have shown weakly coupled superconductivity in SnAs, and recent electronic band-structure calculations have hinted at the existence of possible topologically protected states in this material.
JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM
(2022)
Article
Materials Science, Multidisciplinary
A. D. Mahabir, A. Balatsky, J. T. Haraldsen
Summary: The study examines the effects and interactions of two electronic bands with negative electronic compressibility in a two-dimensional electron gas, showing how effective mass and relative permittivity relate to critical carrier density. It demonstrates the significant impact of second band population and interband coupling on crossover carrier density, and suggests a potential method for identifying multiband electronic systems based on precise bulk electronic properties measurements. Investigating the NEC in the 2DEG at the LAO/STO interface, it determines the likely realization of a two-band 2DEG and provides general limits on interband coupling relative to electronic band population.
Article
Chemistry, Multidisciplinary
Biswajit Pabi, Jakub Sebesta, Richard Korytar, Oren Tal, Atindra Nath Pal
Summary: In contrast to silicon-based transistors, single molecule junctions can be gated by simple mechanical means. The molecular orientation is a new degree of freedom that can be used to optimize mechanically gated molecular junctions.
Article
Engineering, Electrical & Electronic
Monika Moun, Anshu Sirohi, Goutam Sheet
Summary: Silicon, known as an ideal candidate for the semiconductor industry, has been found to exhibit superconducting properties which are insensitive to carrier type and crystal facets. This discovery opens up new possibilities for applications in superconducting nano-electronics.
ACS APPLIED ELECTRONIC MATERIALS
(2021)
Article
Nanoscience & Nanotechnology
YuN Moiseev
Summary: A low-dimensional system with a high polarizability-LB film of ion-exchange polymer on the graphite surface was studied using the STS method. At room temperature, a conductivity peak near zero displacement and excited states on the film surface were observed. At 77 K, in addition to the conductivity peak, a BCS-like gap was also observed. These phenomena are likely to be manifestations of coherence in the electron-medium interaction, possibly indicating superconductivity in this system even at room temperature.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2023)
Article
Nanoscience & Nanotechnology
Man Kit Cheng, Cheuk Yin Ng, Sui Lun Ho, Omargeldi Atanov, Wai Ting Tai, Jing Liang, Rolf Lortz, Iam Keong Sou
Summary: A top-down approach is used to fabricate 1D nanowires or nanoribbons of Bi2Te3/Fe1+yTe heterostructures, showing intact structure and preserved interfacial superconductivity. The electrical transport and Andreev reflection point contact spectroscopy experiments confirm the twin-gap structure and enhanced fluctuation effects in the nanowires. The presence of an Andreev bound state and the possible topological nature of superconductivity are discussed, along with the emerging ferromagnetism in the Fe1+yTe layer.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Physics, Multidisciplinary
Kazuki Isoyama, Naotaka Yoshikawa, Kota Katsumi, Jeremy Wong, Naoki Shikama, Yuki Sakishita, Fuyuki Nabeshima, Atsutaka Maeda, Ryo Shimano
Summary: This study demonstrates the potential of light-matter interaction as a non-thermal tuning knob to enhance emergent orders, and the non-thermal control of quantum phases. By inducing a transient enhancement of superconductivity through light in an iron chalcogenide superconductor, it validates the Higgs mode response and ultrafast dynamics of two superfluid components.
COMMUNICATIONS PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Yu Wang, Linlu Wu, Zheng Wei, Zijia Liu, Peng Cheng, Yiqi Zhang, Baojie Feng, Guangyu Zhang, Wei Ji, Kehui Wu, Lan Chen
Summary: Quantum confinement has significant effects on the band structure and optoelectronic performance of semiconducting materials. This study detected the quantized electronic states of few-layered MoS2 and investigated the influence of interlayer hybridization and substitutional defects on these states. The results provide insights into the manipulation of electronic states in few-layered TMDs and suggest potential applications in subband transitions, spin splitting, photoexcitation, and electronic devices.
Article
Multidisciplinary Sciences
Svetoslav Kuzmichev, Tatiana Kuzmicheva, Igor Morozov, Alexander Boltalin, Andrey Shilov
Summary: The structure of the superconducting order parameter in LiFeAs is studied using incoherent multiple Andreev reflections effect (IMARE) spectroscopy. SnS junctions show the presence of at least three bulk superconducting order parameters in LiFeAs, and we discuss their symmetry.
SN APPLIED SCIENCES
(2022)
Article
Chemistry, Multidisciplinary
Dmitrii Semenok, Ivan A. Troyan, Andrey Sadakov, Di Zhou, Michele Galasso, Alexander G. Kvashnin, Anna G. Ivanova, Ivan A. Kruglov, Alexey A. Bykov, Konstantin Y. Terent'ev, Alexander Cherepakhin, Oleg A. Sobolevskiy, Kirill S. Pervakov, Alexey Yu Seregin, Toni Helm, Tobias Forster, Audrey D. Grockowiak, Stanley W. Tozer, Yuki Nakamoto, Katsuya Shimizu, Vladimir M. Pudalov, Igor S. Lyubutin, Artem R. Oganov
Summary: Polyhydrides are a new class of superconducting materials with high critical parameters that show promise for sensor applications. A study of lanthanum superhydride LaH10, the best known superconductor of this class, is complicated by its large upper critical magnetic field exceeding 120-160 T. The study revealed that replacing La atoms with magnetic Nd atoms significantly suppresses the superconductivity in LaH10, allowing for control of the compound's critical parameters. By using strong pulsed magnetic fields up to 68 T, the study also found that (La,Nd)H-10 exhibits a linear H-C2(T) relationship proportional to |T - T-C|, challenging the applicability of the Werthamer-Helfand-Hohenberg model for polyhydrides. These experimental findings provide new evidence of the isotropic (s-wave) character of conventional electron-phonon pairing in lanthanum decahydride.
ADVANCED MATERIALS
(2022)
Article
Physics, Multidisciplinary
V. M. Pudalov
Summary: The review discusses key experimental results on a multiphase state in two-dimensional electronic systems, focusing on high mobility Si-field effect structures. The study is important for understanding the physical properties of multiphase systems.
Article
Materials Science, Multidisciplinary
I. A. Golovchanskiy, E. Maltsev, I. Shchetinin, V. A. Vlasenko, P. S. Dzhumaev, K. S. Pervakov, O. Emelyanova, A. Yu Tsvetkov, N. N. Abramov, V. M. Pudalov, V. S. Stolyarov
Summary: In this study, we investigated the characteristics of EuSn2As2 single crystals at different temperatures using magnetization measurements, structural characterization, and broad-band ferromagnetic resonance spectroscopy. We observed the conventional collective acoustic resonance mode of the A-type antiferromagnetic canted state in the Eu sub-lattice, as well as its transition to the paramagnetic resonance above the ordering temperature. Additionally, we observed reproducible additional spectral line, which is associated with the magnetism in the Eu sub-lattice.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Chemistry, Physical
Maxim M. Korshunov, Svetoslav A. Kuzmichev, Tatiana E. Kuzmicheva
Summary: We directly observed temperature-dependent spin excitons in the Andreev spectra of iron-based superconductors. Our observation, combined with other experimental evidence, confirms the extended s-wave order parameter symmetry and indirectly supports the spin-fluctuation mechanism of Cooper pairing.
Article
Physics, Multidisciplinary
A. V. Sadakov, A. V. Muratov, S. A. Kuzmichev, O. A. Sobolevskiy, B. I. Massalimov, A. R. Prishchepa, V. M. Mikhailov, K. S. Pervakov, V. A. Vlasenko, T. E. Kuzmicheva
Summary: The structure of the superconducting order parameter has been determined in weakly underdoped BaFe1.92Ni0.08As2 pnictides, and the temperature dependences of the small and large superconducting gaps have been measured.
Article
Physics, Multidisciplinary
M. V. Golubkov, V. A. Stepanov, A. V. Sadakov, A. S. Usol'tsev, I. V. Morozov
Summary: The characteristics of point Josephson contacts Pb0.6In0.4/KFe2As2 and KFe2As2/KFe2As2 were studied. The temperature dependence of characteristic contact voltages V-C(T) and the dependence of the first current step amplitudes in I-V characteristics on the power of 7.6-GHz electromagnetic radiation were measured. It was found that V-C(T) curves for all contacts can be described in terms of the SIS*IS contact model for superconductors with the s-symmetry of order parameter. It was also proven that the current step oscillation period as a function of microwave power can be approximated with the resistive model of contact with I-S = I(C)sin(phi). The obtained data are consistent with the normal s-symmetry of order parameter.
JOURNAL OF EXPERIMENTAL AND THEORETICAL PHYSICS
(2023)
Article
Physics, Multidisciplinary
T. E. Kuzmicheva, S. A. Kuzmichev, K. S. Pervakov, V. A. Vlasenko
Summary: We compare the structure of superconducting order parameter of overdoped BaFe1.88Ni0.12As2 and underdoped BaFe1.92Ni0.08As2 pnictides with similar T-c around 18.0-18.3 K. Using spectroscopy, we directly determine the magnitudes of the two microscopic superconducting order parameters and discuss their similarity, difference, and possible influence of antiferromagnetic phase on superconducting properties.
Article
Chemistry, Physical
Andrey V. Sadakov, Vladimir A. Vlasenko, Ivan A. Troyan, Oleg A. Sobolevskiy, Dmitrii V. Semenok, Di Zhou, Vladimir M. Pudalov
Summary: A comprehensive study was conducted on vortex phases and dynamics in the high-temperature superconductor YH(6) under a pressure of 200 GPa. The thermal activation energy and its dependence on magnetic field were analyzed using the thermally activated flux flow (TAFF) theory. The vortex phase transition from vortex glass to vortex liquid was studied, and a vortex phase diagram was constructed for superhydrides for the first time. The high flux flow barriers and crossover fields make YH6 an outstanding superconductor compared to other materials.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Leonid Morgun, Svetoslav Kuzmichev, Igor Morozov, Alena Degtyarenko, Andrey Sadakov, Andrey Shilov, Ilya Zhuvagin, Yevgeny Rakhmanov, Tatiana Kuzmicheva
Summary: A comprehensive study of the superconducting properties of underdoped NaFe0.979Co0.021As single crystals is presented, using a combination of upper critical field measurements and incoherent multiple Andreev reflection effect (IMARE) spectroscopy. The study reveals the temperature dependence of the Hc2(T) and the characteristics of the superconducting order parameters.
Article
Chemistry, Multidisciplinary
Ivan A. Troyan, Dmitrii V. Semenok, Anna G. Ivanova, Andrey V. Sadakov, Di Zhou, Alexander G. Kvashnin, Ivan A. Kruglov, Oleg A. Sobolevskiy, Marianna V. Lyubutina, Dmitry S. Perekalin, Toni Helm, Stanley W. Tozer, Maxim Bykov, Alexander F. Goncharov, Vladimir M. Pudalov, Igor S. Lyubutin
Summary: The chemical interaction of Sn with H-2 was studied using X-ray diffraction methods, revealing the superconducting properties and structure of SnH4 tetrahydride, as well as several lower hydrides. SnH4 showed unusual behavior in strong magnetic fields and its electrical resistance temperature dependence did not follow conventional theories. These findings suggest that superhydrides are more similar to cuprates than previously believed.
Article
Chemistry, Physical
A. A. Gippius, A. V. Gunbin, A. V. Tkachev, S. V. Zhurenko, D. I. Fazlizhanova, S. A. Kuzmichev, T. E. Kuzmicheva, V. Yu Verchenko, A. V. Shevelkov
Summary: A comprehensive study of the intermetallic superconductor Mo8Ga41 reveals the presence of an inherent surface superconducting phase in addition to the bulk superconducting phase. The s-wave type single-gap superconducting behavior with enhanced electron-phonon coupling is observed in the bulk phase. The surface phase shows a lower superconducting gap value, indicating a weak-coupling BCS limit. These findings help explain the multi-gap behavior in Mo8Ga41.
Article
Materials Science, Multidisciplinary
I. A. Golovchanskiy, N. N. Abramov, V. A. Vlasenko, K. Pervakov, I. Shchetinin, P. S. Dzhumaev, O. Emelyanova, D. S. Baranov, D. S. Kalashnikov, K. B. Polevoy, V. M. Pudalov, V. S. Stolyarov
Summary: In this paper, we present the results of magnetic resonance spectroscopy on EuFe2As2 single crystals. We observe magnetic resonance responses that can be attributed to antiferromagnetic resonances of the Eu sublattice with orthorhombic crystal structure and different orientations of twin domains relative to the external field. We confirm the validity of the recently proposed spin Hamiltonian with anisotropic Eu-Eu exchange interaction and biquadratic Eu-Fe exchange interaction.
