Artificial Atoms in Magnetic Field: Electronic and Optical Properties

1998 ◽  
Vol 12 (05) ◽  
pp. 471-502 ◽  
Author(s):  
R. Rinaldi

Quantum dots semiconductor heterostructures exhibit optical and electronic properties similar to those of real atoms, due to the delta like dispersion of the density of states. The study of the optical and electronic properties of artificial atoms in high magnetic fields allows the observation of quantum effects typical of the atomic physics. In this work we review the problem of artificial atoms in magnetic fields starting from the single-particle theory up to the problems encountered in the observation of correlation effects when two or more carriers are confined in the dot. The main experiments elucidating the change of the optical and electronic properties of artifical atoms in magnetic fields are also reviewed.

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3355-3359
Author(s):  
I. MIHUT ◽  
C. C. AGOSTA ◽  
C. H. MIELKE ◽  
M. TOKOMOTO

The magnetic breakdown effect can be seen by the growth of new frequencies in the quantum oscillations in clean metals as a function of magnetic field. We have studied the variation of the amplitudes in the quantum oscillations in the resistance (the Shubnikov-de Haas effect) as a function of angle in the quasi-two dimensional-organic conductor κ-(BEDT-TTF)2Cu(NCS)2. The measurements were made by means of a radio frequency (rf) tank circuit (~ 50 MHz) at very high magnetic fields(50T-60T) and low temperature(500 mK). The geometry of the rf excitation we used excited in-plane currents, and therefore we measured the in-plane resistivity. In contrast to conventional transport measurements that measure the inter-plane resistivity, the in-plane resistivity is dominated by the magnetic breakdown frequencies. As a result we measured much higher breakdown frequency amplitudes than conventional transport experiments. As is expected, the angular dependence of the Shubnikov-de Haas frequencies have a 1/cosθ behavior. This is due to the change of the cross sectional area of the tubular Fermi surface as the angle with respect to the magnetic field is changed. The amplitude of the oscillations changes due to the spin splitting factor which takes into account the ratio between the spin splitting and the energy spacing of the Landau levels which also has 1/cosθ behavior. We show that our data agree with the semi-classical theory (Lifshitz-Kosevich formula).


1971 ◽  
Vol 49 (21) ◽  
pp. 3577-3578 ◽  
Author(s):  
K. S. V. Santhanam

Effect of magnetic field on electrochemiluminescence of carbazole has been studied in N,N dimethylformamide. The emission intensity increases with increasing applied field with a tendency to decrease at high magnetic fields. An explanation involving perturbation of triplet–triplet annihilation rate is proposed.


Author(s):  
Xiaoxia Wang ◽  
Fanfan Du ◽  
Yingmei Zhang ◽  
Jie Yang ◽  
Xiaoli Li ◽  
...  

The intercalation of hydrogen ions and lithium ions in MoO3 films is realized by acidic ionic liquid gating, which modifies the electronic and optical properties of MoO3 films, is promising for designing multifunctional devices.


2020 ◽  
Vol 233 ◽  
pp. 03004
Author(s):  
M.F.C. Martins Quintela ◽  
J.C.C. Guerra ◽  
S.M. João

In AA-stacked twisted bilayer graphene, the lower energy bands become completely flat when the twist angle passes through certain specific values: the so-called “magic angles”. The Dirac peak appears at zero energy due to the flattening of these bands when the twist angle is sufficiently small [1-3]. When a constant perpendicular magnetic field is applied, Landau levels start appearing as expected [5]. We used the Kernel Polynomial Method (KPM) [6] as implemented in KITE [7] to study the optical and electronic properties of these systems. The aim of this work is to analyze how the features of these quantities change with the twist angle in the presence of an uniform magnetic field.


2019 ◽  
Vol 21 (38) ◽  
pp. 21200-21204 ◽  
Author(s):  
Thierry Dubroca ◽  
Sungsool Wi ◽  
Johan van Tol ◽  
Lucio Frydman ◽  
Stephen Hill

Dynamic Nuclear Polarization (DNP) can increase the sensitivity of Nuclear Magnetic Resonance (NMR), but it is challenging in the liquid state at high magnetic fields.


Author(s):  
Dennis Whyte

The advantages of high magnetic fields in tokamaks are reviewed, and why they are important in leading to more compact tokamaks. A brief explanation is given of what limits the magnetic field in a tokamak, and why high temperature superconductors (HTSs) are a game changer, not just because of their higher magnetic fields but also for reasons of higher current density and higher operating temperatures. An accelerated pathway to fusion energy is described, defined by the SPARC and ARC tokamak designs. This article is part of a discussion meeting issue ‘Fusion energy using tokamaks: can development be accelerated?’.


1999 ◽  
Vol 59 (22) ◽  
pp. 14473-14483 ◽  
Author(s):  
A. L. Cornelius ◽  
A. J. Arko ◽  
J. L. Sarrao ◽  
J. D. Thompson ◽  
M. F. Hundley ◽  
...  

2020 ◽  
Vol 34 (32) ◽  
pp. 2030007
Author(s):  
Andrei G. Lebed

It was theoretically predicted more than 20 years ago [A. G. Lebed and K. Yamaji, Phys. Rev. Lett. 80, 2697 (1998)], that a triplet quasi-two-dimensional (Q2D) superconductor could restore its superconducting state in parallel magnetic fields, which are higher than its upper critical magnetic field, [Formula: see text]. It is very likely that, recently, such phenomenon has been experimentally discovered in the Q2D superconductor UTe2 by Nicholas Butch, Sheng Ran, and their colleagues and has been confirmed by Japanese–French team. We review our previous theoretical results using such a general method that it describes the reentrant superconductivity in the abovementioned compound and will hopefully describes the similar phenomena, which can be discovered in other Q2D superconductors.


1995 ◽  
Vol 52 (19) ◽  
pp. 13757-13760 ◽  
Author(s):  
Kang-Hun Ahn ◽  
J. H. Oh ◽  
K. J. Chang

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