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Topalovic, D.B.; Arsoski, V.V.; Tadic, M.Z.; Peeters, F.M. |
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Title |
Asymmetric versus symmetric HgTe/CdxHg1-x Te double quantum wells: Bandgap tuning without electric field |
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A1 Journal article |
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Year  |
2020 |
Publication |
Journal Of Applied Physics |
Abbreviated Journal |
J Appl Phys |
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Volume |
128 |
Issue |
6 |
Pages |
064301-64308 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We investigate the electron states in double asymmetric HgTe / Cd x Hg 1 – x Te quantum wells grown along the [ 001 ] direction. The subbands are computed by means of the envelope function approximation applied to the eight-band Kane k . mml:mspace width=“.1em”mml:mspace p model. The asymmetry of the confining potential of the double quantum wells results in a gap opening, which is absent in the symmetric system where it can only be induced by an applied electric field. The bandgap and the subbands are affected by spin-orbit coupling, which is a consequence of the asymmetry of the confining potential. The electron-like and hole-like states are mainly confined in different quantum wells, and the enhanced hybridization between them opens a spin-dependent hybridization gap at a finite in-plane wavevector. We show that both the ratio of the widths of the two quantum wells and the mole fraction of the C d x H g 1 – x Te barrier control both the energy gap between the hole-like states and the hybridization gap. The energy subbands are shown to exhibit inverted ordering, and therefore, a nontrivial topological phase could emerge in the system. |
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Wos |
000561339300001 |
Publication Date |
2020-08-10 |
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ISSN |
0021-8979; 1089-7550 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.2 |
Times cited |
3 |
Open Access |
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Notes |
; This research was funded by the Ministry of Education, Science and Technological Development of the Republic of Serbia and the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.2; 2020 IF: 2.068 |
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Call Number |
UA @ admin @ c:irua:171146 |
Serial |
6453 |
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Author |
Topalovic, D.B.; Arsoski, V.V.; Tadic, M.Z.; Peeters, F.M. |
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Title |
Confined electron states in two-dimensional HgTe in magnetic field : quantum dot versus quantum ring behavior |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
100 |
Issue |
12 |
Pages |
125304 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We investigate the electron states and optical absorption in square- and hexagonal-shaped two-dimensional (2D) HgTe quantum dots and quantum rings in the presence of a perpendicular magnetic field. The electronic structure is modeled by means of the sp(3)d(5)s* tight-binding method within the nearest-neighbor approximation. Both bulklike and edge states appear in the energy spectrum. The bulklike states in quantum rings exhibit Aharonov-Bohm oscillations in magnetic field, whereas no such oscillations are found in quantum dots, which is ascribed to the different topology of the two systems. When magnetic field varies, all the edge states in square quantum dots appear as quasibands composed of almost fully flat levels, whereas some edge states in quantum rings are found to oscillate with magnetic field. However, the edge states in hexagonal quantum dots are localized like in rings. The absorption spectra of all the structures consist of numerous absorption lines, which substantially overlap even for small line broadening. The absorption lines in the infrared are found to originate from transitions between edge states. It is shown that the magnetic field can be used to efficiently tune the optical absorption of HgTe 2D quantum dot and quantum ring systems. |
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Wos |
000486638400007 |
Publication Date |
2019-09-16 |
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ISSN |
2469-9969; 2469-9950 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
3 |
Open Access |
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Notes |
; This work was supported by Projects No. III 41028, No. III 42008, and No. III 45003 funded by the Serbian Ministry of Education, Science and Technological Development, and the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.836 |
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Call Number |
UA @ admin @ c:irua:162787 |
Serial |
5409 |
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Author |
Topalovic, D.B.; Arsoski, V.V.; Pavlovic, S.; Cukaric, N.A.; Tadic, M.Z.; Peeters, F.M. |
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Title |
On improving accuracy of finite-element solutions of the effective-mass Schrodinger equation for interdiffused quantum wells and quantum wires |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Communications in theoretical physics |
Abbreviated Journal |
Commun Theor Phys |
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Volume |
65 |
Issue |
1 |
Pages |
105-113 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We use the Galerkin approach and the finite-element method to numerically solve the effective-mass Schrodinger equation. The accuracy of the solution is explored as it varies with the range of the numerical domain. The model potentials are those of interdiffused semiconductor quantum wells and axially symmetric quantum wires. Also, the model of a linear harmonic oscillator is considered for comparison reasons. It is demonstrated that the absolute error of the electron ground state energy level exhibits a minimum at a certain domain range, which is thus considered to be optimal. This range is found to depend on the number of mesh nodes N approximately as alpha(0) log(e)(alpha 1) (alpha N-2), where the values of the constants alpha(0), alpha(1), and alpha(2) are determined by fitting the numerical data. And the optimal range is found to be a weak function of the diffusion length. Moreover, it was demonstrated that a domain range adaptation to the optimal value leads to substantial improvement of accuracy of the solution of the Schrodinger equation. |
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Place of Publication |
Wallingford |
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ISSN |
0253-6102; 1572-9494 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
0.989 |
Times cited |
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Open Access |
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Approved |
Most recent IF: 0.989 |
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Call Number |
UA @ lucian @ c:irua:133213 |
Serial |
4216 |
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