Level anticrossing effect on electron properties of coupled quantum wells under an in-plane magnetic field

Physica E: Low-dimensional Systems and Nanostructures

2015

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a b s t r a c tWe study linear and non-linear coefficients of the intersubband absorption in InSb-based stepped quantum wells subjected to an in-plane magnetic field. We consider also a transverse electric field to achieve near resonance conditions. Taking into account the two deepest conduction levels and their corresponding Zeeman spin splitting sublevels, we calculate dispersion relations by means of an improved version of Kane model. Besides the known anti-crossing between down and up spin split sublevels, we obtain an extra spin level crossing for some determined parameters. This crossing clearly modifies the absorption spectrum for transitions among the four sublevels considered. We study a low electron density case, when only the first deepest sublevel is occupied, and a high density case with only the highest sublevel empty. We find a similar behavior of the absorption spectrum in both cases.

“…For a wide range of p values we obtain dispersion relations. We refer to them as quasi-paraboloids because pure paraboloid shape is broken at anticrossing points [4].…”

Section: Eigenstatesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Intersubband optical absorption in InSb stepped quantum wells: Effect of spin sublevels crossing

Physica E: Low-dimensional Systems and Nanostructures

2015

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“…To do that we have used the transfer matrix method. 20 Figure 4 shows dispersion relations obtained in this way for In 0.75 Al 0.25 As/ In 0.75 Ga 0.25 As with the electron density n 2D =10 12 cm −2 , corresponding to a Fermi energy F Ӎ 130 meV, which slightly depends on magnetic field ͓see Fig. 4͑b͔͒.…”

Section: A Selectively Doped Heterojunctionmentioning

confidence: 99%

Electron energy spectrum and density of states for nonsymmetric semiconductor heterostructures in an in-plane magnetic field

Vasko³

2006

Phys. Rev. B

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Modifications of spin-splitting dispersion relations and density of states for electrons in nonsymmetric heterostructures under in-plane magnetic field are studied within the envelope function formalism. Spin-orbit interactions, caused by both a slow external potential and the heterojunction potentials ͑which are described by the boundary conditions͒ are taken into account. The interplay between these contributions and the magnetic field contribution to the spin-splitting term in the Hamiltonian is essential when energy amounts resulting from the Zeeman and spin-orbit coupling are of the same order. Such modifications of the energy spectra allow us to separate the spin-orbit splitting contributions due to a slow external potential and due to the heterojunctions. Numerical estimates for a selectively doped heterojunction and quantum well with a narrow-gap region of electron localization are performed.

“…Several peculiarities for transport phenomena in heterostructures have been also discussed [12][13][14][15]. However, these discussions only consider the mix-ing between Pauli contribution and effective 2D spin-orbit interaction.…”

Section: Introductionmentioning

confidence: 99%

Abrupt barrier contribution to electron spin splitting in asymmetric coupled double quantum wells

2014

Indian J Phys

We have studied the behavior of the electronic energy spin-splitting of InGaAs − InAlAs based double quantum wells (narrow gap structures) under in-plane magnetic and transverse electric fields. We have developed an improved 8 × 8 version of the Transfer Matrix Approach that consider contributions from abrupt interfaces and external fields when tunneling through central barrier exists. We have included the Landé g-factor dependence on the external applied field. Also, we have calculated electron density of states and photoluminescence excitation. Variations of the electron spin-splitting energy lead to marked peculiarities in the density of states.Because the density of states is directly related to photoluminescence excitation, these peculiarities are observable by this technique.