Bi2Se3

/Tag: Bi2Se3

Observation of chiral surface excitons in a topological insulator Bi2Se3 [Applied Physical Sciences]

2019-02-21T02:31:36+00:00February 21st, 2019|Categories: Publications|Tags: |

The protected electron states at the boundaries or on the surfaces of topological insulators (TIs) have been the subject of intense theoretical and experimental investigations. Such states are enforced by very strong spin–orbit interaction in solids composed of heavy elements. Here, we study the composite particles—chiral excitons—formed by the Coulomb…

Published in: "PNAS (Ahead)".

Photonic Synapses: Near‐Infrared Annihilation of Conductive Filaments in Quasiplane MoSe2/Bi2Se3 Nanosheets for Mimicking Heterosynaptic Plasticity (Small 7/2019)

2019-02-16T22:37:04+00:00February 16th, 2019|Categories: Publications|Tags: , , |

In article number 1805431, Qing Yang, Ye Zhou, Su‐Ting Han, and co‐workers demonstrate modulated heterosyntic plasticity based on a resistive memory device fabricated with MoSe2/Bi2Se3 heterostructured nanosheets. By modulating the synaptic plasticity between pre‐ and post‐neurons with near‐infrared light, the synaptic system displays more complicated functions.

Published in: "Small".

Photonic Synapses: Near‐Infrared Annihilation of Conductive Filaments in Quasiplane MoSe2/Bi2Se3 Nanosheets for Mimicking Heterosynaptic Plasticity (Small 7/2019)

2019-02-16T08:47:51+00:00February 16th, 2019|Categories: Publications|Tags: , , |

In article number 1805431, Qing Yang, Ye Zhou, Su‐Ting Han, and co‐workers demonstrate modulated heterosyntic plasticity based on a resistive memory device fabricated with MoSe2/Bi2Se3 heterostructured nanosheets. By modulating the synaptic plasticity between pre‐ and post‐neurons with near‐infrared light, the synaptic system displays more complicated functions.

Published in: "Small".

Axion Insulator State with ferromagnetic ordering in CrI3/Bi2Se3/MnBi2Se4 Heterostructure. (arXiv:1902.03372v1 [cond-mat.mtrl-sci])

2019-02-12T02:29:27+00:00February 12th, 2019|Categories: Publications|Tags: , |

Realizing axion insulator state with a uniform magnetization considerably facilitates experimental explorations of the intriguing topological magnetoelectric effect, a hallmark of three-dimensional (3D) topological insulators (TIs). Through density functional theory calculations and four-band model studies, we find that magnetic ions Cr3+ in monolayer CrI3 and Mn2+ in septuple-layer MnBi2Se4 have opposite exchange couplings to the topological surface states of 3D TI Bi2Se3. As an exciting result of such opposite exchange couplings, axion insulator state is realized by a uniform magnetization in CrI3/Bi2Se3/MnBi2Se4 heterostructure. Our work opens up opportunities for exploring topological magnetoelectric effect realized by the uniform magnetization induced axion insulator state in heterostructures of 3D TIs and two-dimensional van der Waals ferromagnetic insulators.

Published in: "arXiv Material Science".

Enhancement of thermoelectric properties over a wide temperature range by lattice disorder and chemical potential tuning in a (CuI)y(Bi2Te3)0.95−x(Bi2Se3)x(Bi2S3)0.05 quaternary system

2019-01-31T16:35:18+00:00January 31st, 2019|Categories: Publications|Tags: |

RSC Adv., 2019, 9,4190-4197DOI: 10.1039/C8RA09280J, Paper Open Access &nbsp This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.Hyunyong Cho, Song Yi Back, Jin Hee Kim, Omkaram Inturu, Ho Seong Lee, Jong-Soo RhyeeTemperature-dependent ZT values of (CuI)y(Bi2Te3)0.95−x(Bi2Se3)x(Bi2S3)0.05 (x = 0.05, 0.2;

Published in: "RSC Advances".

Near‐Infrared Annihilation of Conductive Filaments in Quasiplane MoSe2/Bi2Se3 Nanosheets for Mimicking Heterosynaptic Plasticity

2019-01-26T22:34:44+00:00January 26th, 2019|Categories: Publications|Tags: , , |

Near‐infrared (NIR) irradiation‐modulated heterosynaptic plasticity is experimentally demonstrated based on a resistive random access memory device fabricated with MoSe2/Bi2Se3 heterostructured nanosheet. Modulating heterosynaptic plasticity between pre‐ and postneurons by another modulatory interneuron ensures the computing system to display more complicated functions. NIR annihilation effect in MoSe2/Bi2Se3 nanosheets may open a path toward optical modulated in‐memory computing and artificial retinal prostheses. Abstract It is desirable to imitate synaptic functionality to break through the memory wall in traditional von Neumann architecture. Modulating heterosynaptic plasticity between pre‐ and postneurons by another modulatory interneuron ensures the computing system to display more complicated functions. Optoelectronic devices facilitate the inspiration for high‐performance artificial heterosynaptic systems. Nevertheless, the utilization of near‐infrared (NIR) irradiation to act as a modulatory terminal for heterosynaptic plasticity emulation has not yet been realized. Here, an NIR resistive random access memory (RRAM) is reported, based on quasiplane MoSe2/Bi2Se3 heterostructure in which the anomalous NIR threshold switching and NIR reset operation are realized. Furthermore, it is shown that such an NIR irradiation can be employed as a modulatory terminal to emulate heterosynaptic plasticity. The reconfigurable 2D image recognition is also demonstrated by an RRAM crossbar array. NIR annihilation effect in quasiplane MoSe2/Bi2Se3 nanosheets may open a path toward optical‐modulated in‐memory computing and artificial retinal prostheses.

Published in: "Small".

Near‐Infrared Annihilation of Conductive Filaments in Quasiplane MoSe2/Bi2Se3 Nanosheets for Mimicking Heterosynaptic Plasticity

2019-01-21T22:36:50+00:00January 21st, 2019|Categories: Publications|Tags: , , |

Near‐infrared (NIR) irradiation‐modulated heterosynaptic plasticity is experimentally demonstrated based on a resistive random access memory device fabricated with MoSe2/Bi2Se3 heterostructured nanosheet. Modulating heterosynaptic plasticity between pre‐ and postneurons by another modulatory interneuron ensures the computing system to display more complicated functions. NIR annihilation effect in MoSe2/Bi2Se3 nanosheets may open a path toward optical modulated in‐memory computing and artificial retinal prostheses. Abstract It is desirable to imitate synaptic functionality to break through the memory wall in traditional von Neumann architecture. Modulating heterosynaptic plasticity between pre‐ and postneurons by another modulatory interneuron ensures the computing system to display more complicated functions. Optoelectronic devices facilitate the inspiration for high‐performance artificial heterosynaptic systems. Nevertheless, the utilization of near‐infrared (NIR) irradiation to act as a modulatory terminal for heterosynaptic plasticity emulation has not yet been realized. Here, an NIR resistive random access memory (RRAM) is reported, based on quasiplane MoSe2/Bi2Se3 heterostructure in which the anomalous NIR threshold switching and NIR reset operation are realized. Furthermore, it is shown that such an NIR irradiation can be employed as a modulatory terminal to emulate heterosynaptic plasticity. The reconfigurable 2D image recognition is also demonstrated by an RRAM crossbar array. NIR annihilation effect in quasiplane MoSe2/Bi2Se3 nanosheets may open a path toward optical‐modulated in‐memory computing and artificial retinal prostheses.

Published in: "Small".

Giant longitudinal negative magneto-resistance under perpendicular magnetic field in Bi$_{2-x}$Fe$_x$Se$_{3-x}$S$_x$ Topological insulators. (arXiv:1901.06231v1 [cond-mat.str-el])

2019-01-21T04:30:50+00:00January 21st, 2019|Categories: Publications|Tags: |

The magnetic, magneto-transport and ARPES studies of Fe and S co-doped Bi2Se3 were investigated. With doping concentration magneto-resistance (MR) gradually decreases and for a certain doping concentration giant negative MR is observed which persists up to room temperature. Magnetic measurement indicates that the negative MR is observed when ferromagnetic ordering is induced with Fe doping. The magnetic ordering can be attributed with the RKKY interaction. Positive MR reappears with larger doping concentration which may be attributed to the decrease of FM ordering due to the turning off of the spin-orbit coupling leading to the destruction of non-trivial bulk state. This in-effect de-hybridizes the conduction band with the Fe spin. The ARPES data also indicates that above a critical doping concentration (x>0.09) the non-trivial bulk state is completely destroyed.

Published : "arXiv Mesoscale and Nanoscale Physics".

Near‐Infrared Annihilation of Conductive Filaments in Quasiplane MoSe2/Bi2Se3 Nanosheets for Mimicking Heterosynaptic Plasticity

2019-01-18T10:37:27+00:00January 18th, 2019|Categories: Publications|Tags: , , |

Near‐infrared (NIR) irradiation‐modulated heterosynaptic plasticity is experimentally demonstrated based on a resistive random access memory device fabricated with MoSe2/Bi2Se3 heterostructured nanosheet. Modulating heterosynaptic plasticity between pre‐ and postneurons by another modulatory interneuron ensures the computing system to display more complicated functions. NIR annihilation effect in MoSe2/Bi2Se3 nanosheets may open a path toward optical modulated in‐memory computing and artificial retinal prostheses. Abstract It is desirable to imitate synaptic functionality to break through the memory wall in traditional von Neumann architecture. Modulating heterosynaptic plasticity between pre‐ and postneurons by another modulatory interneuron ensures the computing system to display more complicated functions. Optoelectronic devices facilitate the inspiration for high‐performance artificial heterosynaptic systems. Nevertheless, the utilization of near‐infrared (NIR) irradiation to act as a modulatory terminal for heterosynaptic plasticity emulation has not yet been realized. Here, an NIR resistive random access memory (RRAM) is reported, based on quasiplane MoSe2/Bi2Se3 heterostructure in which the anomalous NIR threshold switching and NIR reset operation are realized. Furthermore, it is shown that such an NIR irradiation can be employed as a modulatory terminal to emulate heterosynaptic plasticity. The reconfigurable 2D image recognition is also demonstrated by an RRAM crossbar array. NIR annihilation effect in quasiplane MoSe2/Bi2Se3 nanosheets may open a path toward optical‐modulated in‐memory computing and artificial retinal prostheses.

Published in: "Small".

Oxygen-induced in-situ manipulation of the interlayer coupling and exciton recombination in Bi2Se3/MoS2 2D heterostructures. (arXiv:1901.01310v1 [cond-mat.mtrl-sci])

2019-01-08T02:29:36+00:00January 8th, 2019|Categories: Publications|Tags: , , , |

2D heterostructures are more than a sum of the parent 2D materials, but are also a product of the interlayer coupling, which can induce new properties. In this paper we present a method to tune the interlayer coupling in Bi2Se3/MoS2 2D heterostructures by regulating the oxygen presence in the atmosphere, while applying laser or thermal energy. Our data suggests the interlayer coupling is tuned through the diffusive intercalation and de-intercalation of oxygen molecules. When one layer of Bi2Se3 is grown on monolayer MoS2, an influential interlayer coupling is formed that quenches the signature photoluminescence (PL) peaks. However, thermally annealing in the presence of oxygen disrupts the interlayer coupling, facilitating the emergence of the MoS2 PL peak. DFT calculations predict intercalated oxygen increases the interlayer separation ~17%, disrupting the interlayer coupling and inducing the layers to behave more electronically independent. The interlayer coupling can then be restored by thermally annealing in N2 or Ar, where the peaks will re-quench. Hence, this is an interesting oxygen-induced switching between “non-radiative” and “radiative” exciton recombination. This switching can also be accomplished locally, controllably, and reversibly using a low-power focused laser, while changing the environment from pure N2 to air. This allows for the interlayer coupling to be precisely manipulated with submicron spatial resolution, facilitating site-programmable 2D light-emitting pixels whose emission intensity could be precisely varied by a factor exceeding 200x. Our results show that these atomically-thin 2D heterostructures may be excellent candidates for oxygen sensing.

Published in: "arXiv Material Science".

Growth, Characterization and High Field Magneto-Conductivity of Co0.1Bi2Se3 Topological Insulator. (arXiv:1812.11713v1 [cond-mat.mtrl-sci])

2019-01-01T02:29:24+00:00January 1st, 2019|Categories: Publications|Tags: |

We report the crystal growth as well as transport properties of Co added Bi2Se3 single crystals. The values of the lattice parameters a and b for Co added sample were observed to increase as compared to the pure Bi2Se3. The Raman spectroscopy displayed higher Raman shift of corresponding vibrational modes for Co0.1Bi2Se3, and the resistivity curves with and without applied magnetic field shows a metallic behaviour. Both the crystals were subjected to magneto-resistance (MR) measurements under applied fields of 14Tesla. The value of MR is found to decrease from about 380 (5K, 14 Tesla) for Bi2Se3 to 200 degree for Co0.1Bi2Se3. To elaborate the transport properties of pure and Co added Bi2Se3 crystals, the magneto-conductivity is fitted to the HLN (Hikami Larkin Nagaoka) equation and it is found that the charge conduction is mainly dominated by surface driven WAL (weak anti-localization) with negligible bulk WL (weak localization) contribution in both crystals alike. The MH curves of Co0.1Bi2Se3 crystal at different temperatures displayed a combination of both ferromagnetic and diamagnetic behaviour. On the other hand, the Electron Paramagnetic Resonance (EPR) revealed that pure Bi2Se3 is diamagnetic whereas, Co orders ferro-magnetically with resonating field around 3422Oe at room temperature.

Published in: "arXiv Material Science".

A non-contact mutual inductance based measurement of an inhomogeneous topological insulating state in Bi2Se3 single crystals with defects. (arXiv:1812.06909v1 [cond-mat.mtrl-sci])

2018-12-18T02:29:20+00:00December 18th, 2018|Categories: Publications|Tags: , |

Pure Topological Insulating materials preserve a unique electronic state comprising of bulk insulating gap and conducting surface states. Here we use bulk Bi2Se3 single crystals possessing Se vacancy defects as a prototype topological insulator (TI) material for exploring the effect of non-magnetic disorder on the conducting properties of TIs. We employ a sensitive, non-contact, mutual inductance based technique for measuring the surface and bulk contribution to electrical conductivity in the TI. We discern the different contributions, by observing that predominant surface electrical conduction produces linear frequency dependence of the pickup signal while bulk conductivity gives rise to quadratic frequency dependence. We also see an algebraic temperature dependent surface conductivity while an activated bulk conductivity. Using the above we uncover an interplay between surface and bulk contribution to electrical conductivity in the TI as a function of temperatures. In the Bi2Se3 crystals the transformation from surface to bulk dominated electrical transport is found to occur close to 70 K. This temperature range matches well with our results from activated bulk electrical transport results which shows an activation energy scale, delta which is in the millieV range. The gap delta is much less than the bulk band gap in Bi2Se3, and which we argue is associated with defect states in the TI material. To understand our results, we propose a model of a TI comprising of an inhomogeneous low electrically conducting medium (bulk) which is sandwiched between thin two high electrically conducting sheets (surface). The inhomogeneous TI state we argue is generated

Published in: "arXiv Material Science".

Gas‐Generating Nanoplatforms: Material Chemistry, Multifunctionality, and Gas Therapy

2018-12-15T22:33:35+00:00December 15th, 2018|Categories: Publications|Tags: , |

The construction of gas‐generating nanoplatforms (GGNs) plays the determining role for precise gas therapy. The recent developments of the rational design and chemical construction of versatile GGNs for efficient gas therapies are summarized. The biosafety issue, challenges faced, and future developments on the rational construction of GGNs are also discussed for further promotion of their clinical translation. Abstract The fast advances of theranostic nanomedicine enable the rational design and construction of diverse functional nanoplatforms for versatile biomedical applications, among which gas‐generating nanoplatforms (GGNs) have emerged very recently as unique theranostic nanoplatforms for broad gas therapies. Here, the recent developments of the rational design and chemical construction of versatile GGNs for efficient gas therapies by either exogenous physical triggers or endogenous disease‐environment responsiveness are reviewed. These gases involve some therapeutic gases that can directly change disease status, such as oxygen (O2), nitric oxide (NO), carbon monoxide (CO), hydrogen (H2), hydrogen sulfide (H2S) and sulfur dioxide (SO2), and other gases such as carbon dioxide (CO2), dl‐menthol (DLM), and gaseous perfluorocarbon (PFC) for supplementary assistance of the theranostic process. Abundant nanocarriers have been adopted for gas delivery into lesions, including poly(d,l‐lactic‐co‐glycolic acid), micelles, silica/mesoporous silica, organosilica, MnO2, graphene, Bi2Se3, upconversion nanoparticles, CaCO3, etc. Especially, these GGNs have been successfully developed for versatile biomedical applications, including diagnostic imaging and therapeutic use. The biosafety issue, challenges faced, and future developments on the rational construction of GGNs are also discussed for further promotion of their clinical translation to benefit patients.

Published in: "Advanced Materials".

Gas‐Generating Nanoplatforms: Material Chemistry, Multifunctionality, and Gas Therapy

2018-12-13T00:33:54+00:00December 12th, 2018|Categories: Publications|Tags: , |

The construction of gas‐generating nanoplatforms (GGNs) plays the determining role for precise gas therapy. The recent developments of the rational design and chemical construction of versatile GGNs for efficient gas therapies are summarized. The biosafety issue, challenges faced, and future developments on the rational construction of GGNs are also discussed for further promotion of their clinical translation. Abstract The fast advances of theranostic nanomedicine enable the rational design and construction of diverse functional nanoplatforms for versatile biomedical applications, among which gas‐generating nanoplatforms (GGNs) have emerged very recently as unique theranostic nanoplatforms for broad gas therapies. Here, the recent developments of the rational design and chemical construction of versatile GGNs for efficient gas therapies by either exogenous physical triggers or endogenous disease‐environment responsiveness are reviewed. These gases involve some therapeutic gases that can directly change disease status, such as oxygen (O2), nitric oxide (NO), carbon monoxide (CO), hydrogen (H2), hydrogen sulfide (H2S) and sulfur dioxide (SO2), and other gases such as carbon dioxide (CO2), dl‐menthol (DLM), and gaseous perfluorocarbon (PFC) for supplementary assistance of the theranostic process. Abundant nanocarriers have been adopted for gas delivery into lesions, including poly(d,l‐lactic‐co‐glycolic acid), micelles, silica/mesoporous silica, organosilica, MnO2, graphene, Bi2Se3, upconversion nanoparticles, CaCO3, etc. Especially, these GGNs have been successfully developed for versatile biomedical applications, including diagnostic imaging and therapeutic use. The biosafety issue, challenges faced, and future developments on the rational construction of GGNs are also discussed for further promotion of their clinical translation to benefit patients.

Published in: "Advanced Materials".

Possible Experimental Realization of a Basic Z2 Topological Semimetal. (arXiv:1812.01668v1 [cond-mat.mtrl-sci])

2018-12-06T02:29:16+00:00December 6th, 2018|Categories: Publications|Tags: , |

We report experimental and theoretical evidence that GaGeTe is a basic $Z_2$ topological semimetal with three types of charge carriers: bulk-originated electrons and holes as well as surface state electrons. This electronic situation is qualitatively similar to the primer 3D topological insulator Bi2Se3, but important differences account for an unprecedented transport scenario in GaGeTe. High-resolution angle-resolved photoemission spectroscopy combined with advanced band structure calculations show a small indirect energy gap caused by a peculiar band inversion in the textit{T}-point of the Brillouin zone in GaGeTe. An energy overlap of the valence and conduction bands brings both electron- and hole-like carriers to the Fermi level, while the momentum gap between the corresponding dispersions remains finite. We argue that peculiarities of the electronic spectrum of GaGeTe have a fundamental importance for the physics of topological matter and may boost the material’s application potential.

Published in: "arXiv Material Science".

Nematic superconductivity in doped Bi2Se3 topological superconductors. (arXiv:1812.01378v1 [cond-mat.supr-con])

2018-12-05T02:29:17+00:00December 5th, 2018|Categories: Publications|Tags: |

Nematic superconductivity is a novel class of superconductivity characterized by spontaneous rotational symmetry breaking in the superconducting gap amplitude and/or Cooper-pair spins with respect to the underlying lattice symmetry. Doped Bi2Se3 superconductors, such as CuxBi2Se3, SrxBi2Se3, and NbxBi2Se3, are considered as candidates for nematic superconductors, in addition to the anticipated topological superconductivity. Indeed, various bulk probes, such as nuclear magnetic resonance, specific heat, magnetotransport, magnetic torque, and magnetization, have consistently revealed two-fold symmetric behavior in their in-plane magnetic-field-direction dependence, although the underlying crystal lattice possesses three-fold rotational symmetry. More recently, nematic superconductivity is directly visualized using scanning tunneling microscopy and spectroscopy. In this short review, we summarize the current researches on the nematic behavior in superconducting doped Bi2Se3 systems, and discuss issues and perspectives.

Published in: "arXiv Material Science".

Gas‐Generating Nanoplatforms: Material Chemistry, Multifunctionality, and Gas Therapy

2018-12-04T18:34:59+00:00December 4th, 2018|Categories: Publications|Tags: , |

The construction of gas‐generating nanoplatforms (GGNs) plays the determining role for precise gas therapy. The recent developments of the rational design and chemical construction of versatile GGNs for efficient gas therapies are summarized. The biosafety issue, challenges faced, and future developments on the rational construction of GGNs are also discussed for further promotion of their clinical translation. Abstract The fast advances of theranostic nanomedicine enable the rational design and construction of diverse functional nanoplatforms for versatile biomedical applications, among which gas‐generating nanoplatforms (GGNs) have emerged very recently as unique theranostic nanoplatforms for broad gas therapies. Here, the recent developments of the rational design and chemical construction of versatile GGNs for efficient gas therapies by either exogenous physical triggers or endogenous disease‐environment responsiveness are reviewed. These gases involve some therapeutic gases that can directly change disease status, such as oxygen (O2), nitric oxide (NO), carbon monoxide (CO), hydrogen (H2), hydrogen sulfide (H2S) and sulfur dioxide (SO2), and other gases such as carbon dioxide (CO2), dl‐menthol (DLM), and gaseous perfluorocarbon (PFC) for supplementary assistance of the theranostic process. Abundant nanocarriers have been adopted for gas delivery into lesions, including poly(d,l‐lactic‐co‐glycolic acid), micelles, silica/mesoporous silica, organosilica, MnO2, graphene, Bi2Se3, upconversion nanoparticles, CaCO3, etc. Especially, these GGNs have been successfully developed for versatile biomedical applications, including diagnostic imaging and therapeutic use. The biosafety issue, challenges faced, and future developments on the rational construction of GGNs are also discussed for further promotion of their clinical translation to benefit patients.

Published in: "Advanced Materials".

Proximity induced time-reversal topological superconductivity in Bi2Se3 films without phase tuning. (arXiv:1812.00931v1 [cond-mat.supr-con])

2018-12-04T04:30:18+00:00December 4th, 2018|Categories: Publications|Tags: |

Many proposals to generate a time-reversal invariant topological superconducting phase are based on imposing a $pi$ phase difference between the superconducting leads proximitizing a nanostructure. We show that this phase can be induced on a thin film of a topological insulator like Bi$_2$Se$_3$ in proximity to a single s-wave superconductor. In our analysis we take into account the parity degree of freedom of the electronic states which is not included in effective Dirac-like surface theories. We find that the topological phase can be reached when the induced interparity pairing dominates over the intraparity one. Application of an electric field perpendicular to the film extends the range of parameters where the topological phase occurs.

Published : "arXiv Mesoscale and Nanoscale Physics".

Proximity-induced supercurrent through topological insulator based nanowires for quantum computation studies. (arXiv:1811.09127v1 [cond-mat.mes-hall])

2018-11-26T04:30:24+00:00November 26th, 2018|Categories: Publications|Tags: , |

Proximity induced superconducting energy gap in the surface states of topological insulators has been predicted to host the much wanted Majorana fermions for fault tolerant quantum computation. Recent theoretically proposed architectures for topological quantum computation via Majoranas are based on large networks of Kitaevs one dimensional quantum wires, which pose a huge experimental challenge in terms of scalability of the current single nanowire based devices. Here, we address this problem by realizing robust superconductivity in junctions of fabricated topological insulator Bi2Se3 nanowires proximity coupled to conventional s wave superconducting W electrodes. Milling technique possesses great potential in fabrication of any desired shapes and structures at nanoscale level, and therefore can be effectively utilized to scale up the existing single nanowire based design into nanowire based network architectures. We demonstrate the dominant role of ballistic topological surface states in propagating the long range proximity induced superconducting order with high IcRN product in long Bi2Se3 junctions. Large upper critical magnetic fields exceeding the Chandrasekhar Clogston limit suggests the existence of robust superconducting order with spin triplet cooper pairing. An unconventional inverse dependence of IcRN product on the width of the nanowire junction was also observed.

Published : "arXiv Mesoscale and Nanoscale Physics".

Effect of Sr doping on structure, morphology and transport properties of Bi2Se3 epitaxial thin films. (arXiv:1811.04442v1 [cond-mat.mtrl-sci])

2018-11-13T02:29:21+00:00November 13th, 2018|Categories: Publications|Tags: |

We report molecular beam epitaxy growth of Sr-doped Bi2Se3 films on (111) BaF2 substrate, aimed to realize unusual superconducting properties inherent to SrBi2Se3 single crystals. Despite wide range of the compositions, we do not achieve superconductivity. To explore the reason for that we study structural, morphological and electronic properties of the films and compare them to the corresponding properties of the single crystals. The dependence of the c-lattice constant in the films on Sr content appears to be more than an order of magnitude stronger than in the crystals. Correspondingly, all other properties also differ substantially, indicating that Sr atoms get different positions in lattices. We argue that these structural discrepancies come from essential differences in growth conditions. Our research calls for more detailed structural studies and novel growth approaches for design of superconducting SrxBi2Se3 thin films.

Published in: "arXiv Material Science".

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