scholarly journals Optical intersubband transitions in quantum wires with an applied magnetic field

2004 ◽  
Vol 7 (3) ◽  
pp. 283-286
Author(s):  
G.B. Ibragimov ◽  
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Quantum Wires ◽  
Intersubband Transitions

scholarly journals Many-body Spin Interactions in Semiconductor Quantum Wires

2000 ◽  
Vol 53 (4) ◽  
pp. 543 ◽  
Author(s):  
D. J. Reilly ◽  
L. N. Pfeiffer ◽  
G. R. Facer ◽  
K. W. West ◽  
A. S. Dzurak ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Quantum Wires ◽  
Zero Magnetic Field ◽  
Point Contacts ◽  
Many Body ◽  
Temperature Dependent ◽  
Modulation Doping ◽  
Dominant Mechanism ◽  
Spin Interactions

Zero length quantum wires (or point contacts) exhibit unexplained conductance structure close to 0.7 � 2e 2 /h in the absence of an applied magnetic field. We have studied the density- and temperature-dependent conductance of ultra-low-disorder GaAs/AlGaAs quantum wires with nominal lengths l=0 and 2�m, fabricated from structures free of the disorder associated with modulation doping. In a direct comparision we observe structure near 0.7 � 2e 2 /h for l = 0, whereas thel = 2�m wires show structure evolving with increasing electron density to 0.5 � 2e 2 /h in zero magnetic field, the value expected for an ideal spin-split sub-band. Our results suggest the dominant mechanism through which electrons interact can be strongly affected by the length of the 1D region.

scholarly journals Electron-LO-phonon Intrasubband Scattering Rates in a Hollow Cylinder Under the Influence of a Uniform Axial Applied Magnetic Field

2021 ◽  
Author(s):  
Monkami Masale ◽  
Moletlanyi Tshipa
Keyword(s):  
Magnetic Field ◽  
Quantum Number ◽  
Hollow Cylinder ◽  
Applied Magnetic Field ◽  
Ground State ◽  
Quantum Wires ◽  
Phonon Modes ◽  
Inner Radius ◽  
Energy Subbands ◽  
Scattering Rates

Abstract Scattering rates arising from the interactions of electrons with bulk longitudinal optical (LO) phonon modes in a hollow cylinder are calculated as functions of the inner radius and the uniform axial applied magnetic field. Now, the specific nature of electron-phonon interactions mainly depends on the character of the energy spectrum of electrons. As is well known, in cylindrical quantum wires, the application of a parallel magnetic field lifts the double degeneracy of the non-zero azimuthal quantum number states; m≠0; irrespective of all electron's radial quantum number l states. In fact, this Zeeman splitting is such that the m < 0 electron's energy subbands initially decrease with the increase of the parallel applied magnetic field. In a solid cylinder, the lowest-order; {l = 1; m = 0} subband is always the ground state. In a hollow cylinder, however, as the axial applied magnetic field is increased, the electron's energy subbands take turns at becoming the ground state; following the sequence {m=0,-1,-2...-N} of azimuthal quantum numbers. Furthermore, in a hollow cylinder, in general, the electron's energy separations between any two subbands are less than the LO phonon energy except for exceptionally high magnetic fields, and some highest-order quantum number states. In view of this, the discussion of the energy relaxation here is focused mainly on intrasubband scattering of electrons and only within the lowest-order {l = 1; m = 0} electron's energy subband. The intrasubband scattering rates are found to be characterized by shallow minima in their variations with the inner radius, again, for a fixed outer radius. This feature is a consequence of a balance between two seemingly conflicting effects of the electron's confinement by the inner and outer walls of the hollow cylinder. First; increased confinement of the charge carriers generally leads to the enhancement of the rates. Second; the presence of a hole in a hollow cylinder leads to a significant suppression of the scattering rates. The intrasubband scattering rates also show a somewhat parabolic increase in their variations with the applied magnetic field; an increase which is more pronounced in a relatively thick hollow cylinder.

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