scholarly journals A large-energy-gap oxide topological insulator based on the superconductor BaBiO3

2013 ◽  
Vol 9 (11) ◽  
pp. 709-711 ◽  
Author(s):  
Binghai Yan ◽  
Martin Jansen ◽  
Claudia Felser
Keyword(s):  
Topological Insulator ◽  
Energy Gap ◽  
Large Energy

Massive polarons in large-energy-gap polymers

1989 ◽  
Vol 39 (14) ◽  
pp. 10174-10178 ◽  
Author(s):  
R. P. McCall ◽  
J. M. Ginder ◽  
M. G. Roe ◽  
G. E. Asturias ◽  
E. M. Scherr ◽  
...  
Keyword(s):  
Energy Gap ◽  
Large Energy

Transport Properties of Topological Insulator Bi0.83Sb0.17 Nanowires

2015 ◽  
Vol 1785 ◽  
pp. 1-6
Author(s):  
L.A. Konopko ◽  
A.A. Nikolaeva ◽  
T.E. Huber ◽  
J.P. Ansermet
Keyword(s):  
Magnetic Field ◽  
Single Crystal ◽  
Transport Properties ◽  
Topological Insulator ◽  
Energy Gap ◽  
Oscillation Amplitude ◽  
Glass Capillary ◽  
Wire Axis ◽  
Temperature Dependences ◽  
The Wire

ABSTRACTWe have investigated the transport properties of topological insulator based on single-crystal Bi0.83Sb0.17 nanowires. The single-crystal nanowire samples in the diameter range 200 nm – 1.1 μm were prepared by the high frequency liquid phase casting in a glass capillary using an improved Ulitovsky technique; they were cylindrical single-crystals with (1011) orientation along the wire axis. In this orientation, the wire axis makes an angle of 19.5o with the bisector axis C1 in the bisector-trigonal plane. Bi0.83Sb0.17 is a narrow gap semiconductor with energy gap at L point of Brillouin zone ΔE= 21 meV. In accordance with the measurements of the temperature dependence of the resistivity of the samples resistance increases with decreasing temperature, but at low temperatures decrease in the resistance is observed. This effect, decrease in the resistance, is a clear manifestation of the interesting properties of topological insulators - the presence on its surface of a highly conducting zone. The Arrhenius plot of resistance R in samples with diameter d=1.1 µm and d=200 nm indicates a thermal activation behavior with an activation gap ΔE= 21 and 35 meV, respectively, which proves the presence of the quantum size effect in these samples. We found that in the range of diameter 1100 nm - 200 nm when the diameter decreases the energy gap is growing as 1/d. We have investigated magnetoresistance of Bi0.83Sb0.17 nanowires at various magnetic field orientations. From the temperature dependences of Shubnikov de Haas oscillation amplitude for different orientation of magnetic field we have calculated the cyclotron mass mc and Dingle temperature TD for longitudinal and transverse (B||C3 and B||C2) directions of magnetic fields, which equal 1.96*10-2m0, 9.8 K, 8.5*10-3m0 , 9.4 K and 1.5*10-1m0 , 2.8 K respectively. The observed effects are discussed.

Topological Properties in Strained Monolayer Antimony Iodide

2021 ◽  
Vol 38 (11) ◽  
pp. 117301
Author(s):  
Danwen Yuan ◽  
Yuefang Hu ◽  
Yanmin Yang ◽  
Wei Zhang
Keyword(s):  
Topological Insulator ◽  
Topological Insulators ◽  
Energy Gap ◽  
Square Lattice ◽  
Honeycomb Lattice ◽  
Type I ◽  
Topological Properties ◽  
Dirac Semimetal ◽  
Low Dissipation ◽  
Binary Compounds

Two-dimensional (2D) topological insulators present a special phase of matter manifesting unique electronic properties. Till now, many monolayer binary compounds of Sb element, mainly with a honeycomb lattice, have been reported as 2D topological insulators. However, research of the topological insulating properties of the monolayer Sb compounds with square lattice is still lacking. Here, by means of the first-principles calculations, a monolayer SbI with square lattice is proposed to exhibit the tunable topological properties by applying strain. At different levels of the strain, the monolayer SbI shows two different structural phases: buckled square structure and buckled rectangular structure, exhibiting attracting topological properties. We find that in the buckled rectangular phase, when the strain is greater than 3.78%, the system experiences a topological phase transition from a nontrivial topological insulator to a trivial insulator, and the structure at the transition point actually is a Dirac semimetal possessing two type-I Dirac points. In addition, the system can achieve the maximum global energy gap of 72.5 meV in the topological insulator phase, implying its promising application at room temperature. This study extends the scope of 2D topological physics and provides a platform for exploring the low-dissipation quantum electronics devices.

Specific heat evidence for a large energy gap in YBCO

1988 ◽  
Vol 153-155 ◽  
pp. 1020-1021 ◽  
Author(s):  
W. Loram ◽  
K.A. Mirza
Keyword(s):  
Specific Heat ◽  
Energy Gap ◽  
Large Energy

scholarly journals CONTRACTION OF HIGHER ORDER DERIVATIVE SUSY ALGEBRAS IN QUANTUM MECHANICS WITH LARGE ENERGY GAP

1996 ◽  
Vol 11 (17) ◽  
pp. 1417-1428 ◽  
Author(s):  
A.A. ANDRIANOV ◽  
M.V. IOFFE ◽  
F. CANNATA
Keyword(s):  
Energy Gap ◽  
Deep Level ◽  
Linearization Method ◽  
Higher Order ◽  
Large Energy ◽  
Order Derivative ◽  
Singular Behavior ◽  
Higher Derivative ◽  
Higher Order Derivative ◽  
Infinite Energy

Starting from a polynomial (higher-order derivative) quantum mechanical SUSY algebra we study its contraction to the standard SUSYQM in the limit of large energy shifts between the lowest states of the super-Hamiltonian (of Schrödinger type). By a quasi-linearization method we obtain the charges of the higher derivative SUSY algebra in the (singular) limit of infinite energy gap, and find the resulting Hamiltonian. The singular behavior of the potential generated by this construction reflects the existence of the very deep level. Our results can suggest constructions of toy models where large energy splittings between fermionic and bosonic partners do not affect SUSY for other states.

TUNNELING MEASUREMENTS OF THE ENERGY GAP IN HIGH-Tc SUPERCONDUCTORS

1990 ◽  
Vol 04 (02) ◽  
pp. 201-237 ◽  
Author(s):  
J. R. KIRTLEY
Keyword(s):  
Fermi Level ◽  
Density Of States ◽  
Energy Gap ◽  
Large Energy ◽  
Current Status ◽  
High Tc Superconductors ◽  
High Tc ◽  
Gap Anisotropy ◽  
Consistent Picture ◽  
Coherence Lengths

The current status of tunneling measurements of the superconducting density of states near the Fermi level of high-T c superconductors is reviewed. A number of the characteristics of the tunneling data that had previously been considered to be "non-ideal" follow quite naturally from conventional tunneling theory, if the effects of the unusually large energy gap, often unusually small tunneling barriers, and gap anisotropy and/or inhomogeneity are correctly accounted for. Despite formidable problems in making these measurements, due to both the very short coherence lengths and materials problems in these superconductors, a consistent body of data is emerging. A consistent picture can be drawn from this data with the aid of the new modelling presented here.

Large Energy, Wavelength Widely Tunable, Topological Insulator Q-Switched Erbium-Doped Fiber Laser

2014 ◽  
Vol 20 (5) ◽  
pp. 315-322 ◽  
Author(s):  
Yu Chen ◽  
Chujun Zhao ◽  
Shuqing Chen ◽  
Juan Du ◽  
Pinghua Tang ◽  
...  
Keyword(s):  
Fiber Laser ◽  
Topological Insulator ◽  
Large Energy ◽  
Erbium Doped

Thiolate-Protected Au20Clusters with a Large Energy Gap of 2.1 eV

2009 ◽  
Vol 131 (21) ◽  
pp. 7220-7221 ◽  
Author(s):  
Manzhou Zhu ◽  
Huifeng Qian ◽  
Rongchao Jin
Keyword(s):  
Energy Gap ◽  
Large Energy

scholarly journals Resolving the topological classification of bismuth with topological defects

2019 ◽  
Vol 5 (11) ◽  
pp. eaax6996 ◽  
Author(s):  
Abhay Kumar Nayak ◽  
Jonathan Reiner ◽  
Raquel Queiroz ◽  
Huixia Fu ◽  
Chandra Shekhar ◽  
...  
Keyword(s):  
Screw Dislocation ◽  
Topological Insulator ◽  
Energy Gap ◽  
Topological Defects ◽  
Higher Order ◽  
Topological Classification ◽  
Wide Energy Range ◽  
The Status ◽  
The One

The growing diversity of topological classes leads to ambiguity between classes that share similar boundary phenomenology. This is the status of bulk bismuth. Recent studies have classified it as either a strong or a higher-order topological insulator, both of which host helical modes on their boundaries. We resolve the topological classification of bismuth by spectroscopically mapping the response of its boundary modes to a screw-dislocation. We find that the one-dimensional mode, on step-edges, extends over a wide energy range and does not open a gap near the screw-dislocations. This signifies that this mode binds to the screw-dislocation, as expected for a material with nonzero weak indices. We argue that the small energy gap, at the time reversal invariant momentum L, positions bismuth within the critical region of a topological phase transition between a higher-order topological insulator and a strong topological insulator with nonzero weak indices.

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