TY  - CONF
AU  - Topalović, Dušan
AU  - Arsoski, Vladimir
AU  - Tadić, Milan Ž.
AU  - Peeters, François M.
PY  - 2019
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11878
AB  - The quantum spin Hall (QSH) effect is a unique phase of matter characterized by a pair of helical edge states protected by time-reversal symmetry. The existence of this phase was first theoretically proposed for graphene [1]. However, experiments showed that spin-orbit interaction in low-mass C atoms is too small to open an energy gap [2]. Therefore, greater attention is paid to materials that are composed of heavier atoms in which relativistic effects are more pronounced. A notable example is thin HgTe/CdTe quantum well (QW) where the QSH effect was theoretically predicted [3] and experimentally realized [4]. By using effective models it has been found that double symmetric HgTe/CdxHg1-xTe QW may also possess a topological nontrivial phase [5, 6]. Structures of this type exhibit interesting 3/2 pseudospin based physics similar to that in bilayer graphene without valley degeneracy [6]. We investigate the electronic properties of double asymmetric HgTe/CdxHg1-xTe QW with [001] orientation. The electronic structure is calculated within the framework of the Kane k · p theory [7]. We choose the common eight-band basis set that describes the coupling between the Γ6, Γ7, and Γ8 bands. We assumed that the model parameters change abruptly along the structure. Also, the difference between the valence bands in HgTe and CdTe is assumed to vary linearly with mole fraction. The theoretical model is based on the Burt envelope function approach on expansion in plane waves is used in our numerical calculations. The results obtained for the electronic structure indicate that a quantum phase transition can occur in asymmetric double QW when a perpendicular electric field is applied. Besides an external field the phase transition could be controlled by varying geometric parameters of the wells and the mole fraction in barriers.
PB  - Belgrade : Vinča Institute of Nuclear Sciences, University of Belgrade
C3  - PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts
T1  - Tunable quantum phase transitions in asymmetric HgTe/CdxHg1-xTe double quantum wells
SP  - 109
EP  - 109
UR  - https://hdl.handle.net/21.15107/rcub_vinar_11878
ER  - 

@conference{
author = "Topalović, Dušan and Arsoski, Vladimir and Tadić, Milan Ž. and Peeters, François M.",
year = "2019",
abstract = "The quantum spin Hall (QSH) effect is a unique phase of matter characterized by a pair of helical edge states protected by time-reversal symmetry. The existence of this phase was first theoretically proposed for graphene [1]. However, experiments showed that spin-orbit interaction in low-mass C atoms is too small to open an energy gap [2]. Therefore, greater attention is paid to materials that are composed of heavier atoms in which relativistic effects are more pronounced. A notable example is thin HgTe/CdTe quantum well (QW) where the QSH effect was theoretically predicted [3] and experimentally realized [4]. By using effective models it has been found that double symmetric HgTe/CdxHg1-xTe QW may also possess a topological nontrivial phase [5, 6]. Structures of this type exhibit interesting 3/2 pseudospin based physics similar to that in bilayer graphene without valley degeneracy [6]. We investigate the electronic properties of double asymmetric HgTe/CdxHg1-xTe QW with [001] orientation. The electronic structure is calculated within the framework of the Kane k · p theory [7]. We choose the common eight-band basis set that describes the coupling between the Γ6, Γ7, and Γ8 bands. We assumed that the model parameters change abruptly along the structure. Also, the difference between the valence bands in HgTe and CdTe is assumed to vary linearly with mole fraction. The theoretical model is based on the Burt envelope function approach on expansion in plane waves is used in our numerical calculations. The results obtained for the electronic structure indicate that a quantum phase transition can occur in asymmetric double QW when a perpendicular electric field is applied. Besides an external field the phase transition could be controlled by varying geometric parameters of the wells and the mole fraction in barriers.",
publisher = "Belgrade : Vinča Institute of Nuclear Sciences, University of Belgrade",
journal = "PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts",
title = "Tunable quantum phase transitions in asymmetric HgTe/CdxHg1-xTe double quantum wells",
pages = "109-109",
url = "https://hdl.handle.net/21.15107/rcub_vinar_11878"
}

Topalović, D., Arsoski, V., Tadić, M. Ž.,& Peeters, F. M.. (2019). Tunable quantum phase transitions in asymmetric HgTe/CdxHg1-xTe double quantum wells. in PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts
Belgrade : Vinča Institute of Nuclear Sciences, University of Belgrade., 109-109.
https://hdl.handle.net/21.15107/rcub_vinar_11878

Topalović D, Arsoski V, Tadić MŽ, Peeters FM. Tunable quantum phase transitions in asymmetric HgTe/CdxHg1-xTe double quantum wells. in PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts. 2019;:109-109.
https://hdl.handle.net/21.15107/rcub_vinar_11878 .

Topalović, Dušan, Arsoski, Vladimir, Tadić, Milan Ž., Peeters, François M., "Tunable quantum phase transitions in asymmetric HgTe/CdxHg1-xTe double quantum wells" in PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts (2019):109-109,
https://hdl.handle.net/21.15107/rcub_vinar_11878 .

TY  - CONF
AU  - Topalović, Dušan
AU  - Arsoski, Vladimir
AU  - Čukarić, Nemanja
AU  - Tadić, Milan Ž.
AU  - Peeters, F. M.
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/13347
AB  - After decades of applications for photovoltaic devices, HgTe has recently gained popularity due to its unique topological properties. As a matter of fact, HgTe quantum wells host the gapless edge states, which are protected by time reversal symmetry. Those states were predicted by comprehensive theory  [1], which was then confirmed by experiment [2]. In addition to HgTe quantum wells, HgTe quantum dots have been recently explored. Quantum confined states in HgTe colloidal quantum dots [3] were demonstrated to allow for fine tuning of the energy spectra from close to near infrared region [4-6].  We investigate the electronic and optical properties of square shaped HgTe quantum dots. The electronic structure is calculated by means of the nearest neighbour tight binding (TB) method in a sp3d5s*basis where spin-orbit coupling is included [7]. A large number of hopping parameters is taken into account with the aim to accurately describe invertedband structure. The exciton states are modelled as the first-order corrections of the single particle spectra due to the Coulomb and exchange interactions [8]. The dipole moment is determined by including only the intraorbital terms, which was previously demonstrated to be a reasonable approximation for graphene, silicene, and phosphorene quantum dots [9,10]. And the appearance of trivial edge states is avoided by removing the dangling bonds from the quantum dot. The result of this study is that the peculiar edge states exist in square HgTe quantum dots. Furthermore, influence of in-plane electric field and perpendicular magnetic field on the optical absorption spectra is investigated. The edge and bulk states are found to behave differently in external fields, and those differences are explored and analyzed in detail.
PB  - Belgrade : Institute of Physics Belgrade
C3  - PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts
T1  - Electronic and optical properties of square HgTe quantum dots
SP  - 98
EP  - 98
UR  - https://hdl.handle.net/21.15107/rcub_vinar_13347
ER  - 

@conference{
author = "Topalović, Dušan and Arsoski, Vladimir and Čukarić, Nemanja and Tadić, Milan Ž. and Peeters, F. M.",
year = "2017",
abstract = "After decades of applications for photovoltaic devices, HgTe has recently gained popularity due to its unique topological properties. As a matter of fact, HgTe quantum wells host the gapless edge states, which are protected by time reversal symmetry. Those states were predicted by comprehensive theory  [1], which was then confirmed by experiment [2]. In addition to HgTe quantum wells, HgTe quantum dots have been recently explored. Quantum confined states in HgTe colloidal quantum dots [3] were demonstrated to allow for fine tuning of the energy spectra from close to near infrared region [4-6].  We investigate the electronic and optical properties of square shaped HgTe quantum dots. The electronic structure is calculated by means of the nearest neighbour tight binding (TB) method in a sp3d5s*basis where spin-orbit coupling is included [7]. A large number of hopping parameters is taken into account with the aim to accurately describe invertedband structure. The exciton states are modelled as the first-order corrections of the single particle spectra due to the Coulomb and exchange interactions [8]. The dipole moment is determined by including only the intraorbital terms, which was previously demonstrated to be a reasonable approximation for graphene, silicene, and phosphorene quantum dots [9,10]. And the appearance of trivial edge states is avoided by removing the dangling bonds from the quantum dot. The result of this study is that the peculiar edge states exist in square HgTe quantum dots. Furthermore, influence of in-plane electric field and perpendicular magnetic field on the optical absorption spectra is investigated. The edge and bulk states are found to behave differently in external fields, and those differences are explored and analyzed in detail.",
publisher = "Belgrade : Institute of Physics Belgrade",
journal = "PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts",
title = "Electronic and optical properties of square HgTe quantum dots",
pages = "98-98",
url = "https://hdl.handle.net/21.15107/rcub_vinar_13347"
}

Topalović, D., Arsoski, V., Čukarić, N., Tadić, M. Ž.,& Peeters, F. M.. (2017). Electronic and optical properties of square HgTe quantum dots. in PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts
Belgrade : Institute of Physics Belgrade., 98-98.
https://hdl.handle.net/21.15107/rcub_vinar_13347

Topalović D, Arsoski V, Čukarić N, Tadić MŽ, Peeters FM. Electronic and optical properties of square HgTe quantum dots. in PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts. 2017;:98-98.
https://hdl.handle.net/21.15107/rcub_vinar_13347 .

Topalović, Dušan, Arsoski, Vladimir, Čukarić, Nemanja, Tadić, Milan Ž., Peeters, F. M., "Electronic and optical properties of square HgTe quantum dots" in PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts (2017):98-98,
https://hdl.handle.net/21.15107/rcub_vinar_13347 .