Electronic properties of two- and three-dimensional quasicrystalline model systems in a magnetic field

1997 ◽  
Vol 56 (13) ◽  
pp. 8026-8031 ◽  
Author(s):  
H. Schwabe ◽  
G. Kasner ◽  
H. Böttger
Keyword(s):  
Magnetic Field ◽  
Electronic Properties ◽  
Three Dimensional ◽  
Model Systems

scholarly journals Electronic properties of the topological insulators Bi₂Se₃ and Bi₂Te₃

2021 ◽  
Author(s):  
◽  
Robin Gühne
Keyword(s):  
Electronic Properties ◽  
Single Crystals ◽  
Topological Insulators ◽  
Three Dimensional ◽  
Surface States ◽  
Quantitative Agreement ◽  
Model Systems ◽  
Electronic Spin ◽  
Band Inversion ◽  
A Charge

<p>The three-dimensional topological insulators Bi₂Se₃ and Bi₂Te₃ are model systems of a new class of materials with an insulating bulk and gapless surface states. Their small band gaps and the heavy elements are essential for the topologically non-trivial band structure, but these features are similarly responsible for other remarkable properties, such as their high thermoelectric performance.  This thesis investigates the electronic properties of the topological insulators Bi₂Se₃ and Bi₂Te₃ with a broad range of experimental methods. Ferromagnetism in Mn doped Bi₂Te₃ is shown to disappear under sample sintering. A surprisingly large magnetoresistance and a charge carrier independent change in the sign of the thermopower with increasing Mn content are discussed.¹²⁵Te nuclear magnetic resonance (NMR) of Bi₂Te₃ single crystals suggest an unusual electronic spin susceptibility and complex NMR shifts. The quadrupole interaction of ²⁰⁹Bi nuclei in Bi₂Se₃ single crystals is shown to be a signature of the band inversion in quantitative agreement with first-principle calculations. Furthermore, it is proposed that the strong spin-orbit coupling of conduction electrons causes a non-trivial orientation dependent quadrupole splitting of the ²⁰⁹Bi resonance.</p>

scholarly journals Electronic properties of the topological insulators Bi₂Se₃ and Bi₂Te₃

2021 ◽  
Author(s):  
◽  
Robin Gühne
Keyword(s):  
Electronic Properties ◽  
Single Crystals ◽  
Topological Insulators ◽  
Three Dimensional ◽  
Surface States ◽  
Quantitative Agreement ◽  
Model Systems ◽  
Electronic Spin ◽  
Band Inversion ◽  
A Charge

<p>The three-dimensional topological insulators Bi₂Se₃ and Bi₂Te₃ are model systems of a new class of materials with an insulating bulk and gapless surface states. Their small band gaps and the heavy elements are essential for the topologically non-trivial band structure, but these features are similarly responsible for other remarkable properties, such as their high thermoelectric performance.  This thesis investigates the electronic properties of the topological insulators Bi₂Se₃ and Bi₂Te₃ with a broad range of experimental methods. Ferromagnetism in Mn doped Bi₂Te₃ is shown to disappear under sample sintering. A surprisingly large magnetoresistance and a charge carrier independent change in the sign of the thermopower with increasing Mn content are discussed.¹²⁵Te nuclear magnetic resonance (NMR) of Bi₂Te₃ single crystals suggest an unusual electronic spin susceptibility and complex NMR shifts. The quadrupole interaction of ²⁰⁹Bi nuclei in Bi₂Se₃ single crystals is shown to be a signature of the band inversion in quantitative agreement with first-principle calculations. Furthermore, it is proposed that the strong spin-orbit coupling of conduction electrons causes a non-trivial orientation dependent quadrupole splitting of the ²⁰⁹Bi resonance.</p>

1,1’-Biaceanthrylene and 2,2'-Biaceanthrylene: Models for Linking Larger Polycyclic Aromatic Hydrocarbons via Five-Membered Rings

2019 ◽  
Author(s):  
Yachu Du ◽  
Kyle Plunkett
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Electronic Properties ◽  
Aromatic Hydrocarbons ◽  
Model Systems ◽  
Redox Potentials ◽  
Dimer Model ◽  
Optical And Electronic Properties ◽  
Polycyclic Aromatic

We show that polycyclic aromatic hydrocarbon (PAH) chromophores that are linked between two five-membered rings can access planarized structures with reduced optical gaps and redox potentials. Two aceanthrylene chromophores were connected into dimer model systems with the chromophores either projected outward (2,2’-biaceanthrylene) or inward (1,1’-biaceanthrylene) and the optical and electronic properties were compared. Only the planar 2,2’-biaceanthrylene system showed significant reductions of the optical gaps (1 eV) and redox potentials in relation to the aceanthrylene monomer.<br>

1,1’-Biaceanthrylene and 2,2'-Biaceanthrylene: Models for Linking Larger Polycyclic Aromatic Hydrocarbons via Five-Membered Rings

2019 ◽  
Author(s):  
Yachu Du ◽  
Kyle Plunkett
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Electronic Properties ◽  
Aromatic Hydrocarbons ◽  
Model Systems ◽  
Redox Potentials ◽  
Dimer Model ◽  
Optical And Electronic Properties ◽  
Polycyclic Aromatic

We show that polycyclic aromatic hydrocarbon (PAH) chromophores that are linked between two five-membered rings can access planarized structures with reduced optical gaps and redox potentials. Two aceanthrylene chromophores were connected into dimer model systems with the chromophores either projected outward (2,2’-biaceanthrylene) or inward (1,1’-biaceanthrylene) and the optical and electronic properties were compared. Only the planar 2,2’-biaceanthrylene system showed significant reductions of the optical gaps (1 eV) and redox potentials in relation to the aceanthrylene monomer.<br>

Casimir forces and vacuum energy

2017 ◽  
Author(s):  
Serge Reynaud ◽  
Astrid Lambrecht
Keyword(s):  
Casimir Force ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Thermal Fluctuations ◽  
Model Systems ◽  
Vacuum Field ◽  
Force Measurements ◽  
Casimir Forces ◽  
Current State ◽  
Field Fluctuations

The Casimir force is an effect of quantum vacuum field fluctuations, with applications in many domains of physics. The ideal expression obtained by Casimir, valid for perfect plane mirrors at zero temperature, has to be modified to take into account the effects of the optical properties of mirrors, thermal fluctuations, and geometry. After a general introduction to the Casimir force and a description of the current state of the art for Casimir force measurements and their comparison with theory, this chapter presents pedagogical treatments of the main features of the theory of Casimir forces for one-dimensional model systems and for mirrors in three-dimensional space.

Multiple characteristics of three‐dimensional radiative Cross fluid with velocity slip and inclined magnetic field over a stretching sheet

Heat Transfer ◽  
2021 ◽  
Author(s):  
Hafiz Abdul Wahab ◽  
Syed Zahir Hussain Shah ◽  
Assad Ayub ◽  
Zulqurnain Sabir ◽  
Muhammad Bilal ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Stretching Sheet ◽  
Three Dimensional ◽  
Velocity Slip ◽  
Inclined Magnetic Field ◽  
Multiple Characteristics

Magneto convective flow of casson nanofluid due to Stefan blowing in the presence of bio-active mixers

2021 ◽  
pp. 239779142110166
Author(s):  
Venkatesh Puneeth ◽  
Sarpabhushana Manjunatha ◽  
Bijjanal Jayanna Gireesha ◽  
Rama Subba Reddy Gorla
Keyword(s):  
Magnetic Field ◽  
Brownian Motion ◽  
Convective Flow ◽  
Three Dimensional ◽  
Induced Magnetic Field ◽  
Density Profiles ◽  
Casson Nanofluid ◽  
And Brownian Motion ◽  
Similarity Transformations ◽  
The Mathematical Model

The induced magnetic field for three-dimensional bio-convective flow of Casson nanofluid containing gyrotactic microorganisms along a vertical stretching sheet is investigated. The movement of these microorganisms cause bioconvection and they act as bio-active mixers that help in stabilising the nanoparticles in the suspension. The two forces, Thermophoresis and Brownian motion are incorporated in the Mathematical model along with Stefan blowing. The resulting model is transformed to ordinary differential equations using similarity transformations and are solved using [Formula: see text] method. The Velocity, Induced Magnetic field, Temperature, Concentration of Nanoparticles, and Motile density profiles are interpreted graphically. It is observed that the Casson parameter decreases the flow velocity and enhances the temperature, concentration, and motile density profiles and also it is noticed that the blowing enhances the nanofluid profiles whereas, suction diminishes the nanofluid profiles. On the other hand, it is perceived that the rate of heat conduction is enhanced with Thermophoresis and Brownian motion.

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