Interface States in Subband Structure of Semiconductor Quantum Wells

Abstract

An analytical investigation is made of semiconductor quantum-well subband structures using the three-band Kane model. The analysis is based on the assumption, that electron and light hole masses are much smaller than heavy hole mass in the heterostructure. It is demonstrated, that some anomalies in the subband spectrum are due to the interaction with interface states, others are generated by the repulsion between the subbands near the points of their quasiintersections. For the heterostructure, composed of the gapless layer in a finite-gap bulk material, the interface state is found to cause a nonmonotonous dependence of the gap on the layer thickness.Es wird eine analytische Untersuchung von Halbleiter-Quantenwell-Subbandstrukturen mit dem Kaneschen Dreibandermodell durchgefuhrt. Die Analyse beruht auf der Annahme, daR Elektronen-und Leichte-Locher-Massen vie1 kleiner sind als die Masse schwerer Locher in der Heterostruktur. Es wird gezeigt, daR einige Anomalien im Subbandspektrum durch die Wechselwirkung mit Grenzflachenzustanden hervorgerufen werden, andere werden durch die AbstoDung zwischen den Subbandern in der Nahe ihrer Quasiuberschneidungspunkte generiert. Fur die Heterostrukturen, die aus einer gaplosen Schicht in einem Volumenmaterial mit endlicher Bandlucke zusammengesetzt sind, wird gefunden, daD die Grenzflache eine monotone Abhangigkeit der Bandlucke von der Schichtdicke verursacht.

Two-dimensional semimetal in a wide HgTe quantum well: Magnetotransport and energy spectrum

“…A great variety of two-dimensional electron and hole systems based on these materials can be realized depending on the quantum well width (d) and content of cadmium in the Hg 1−x Cd x Te well and Hg 1−y Cd y Te barriers. It is now well established that the energy spectrum in CdTe/HgTe/CdTe quantum well at d = d c 6.5 nm is gapless 1 and is close to the linear Dirac-like spectrum at small quasimomentum k. 2 When the thickness d < d c (i.e., when the HgTe quantum well is narrow), the ordering of energy subbands of spatial quantization is analogous to that in conventional narrow-gap semiconductors; the highest valence subband at k = 0 is formed from the heavy-hole 8 states, while the lowest electron subband is formed both from the 6 states and light-hole 8 states. For a thick HgTe layer, d > d c , the quantum well is in the inverted regime; the main electron subband is formed from the heavy-hole 8 states, 3 whereas the subband formed from the 6 states and light-hole 8 states sinks into the valence band.…”

Activation transport under quantum Hall regime in HgTe-based heterostructure

“…In the inverted regime of HgTe QW the first sizequantized heavy-hole subband H1 becomes the lowest conduction band as the theory [13,14] predicts an electronlike effective mass for it. The highest valence band is now the second size-quantized heavy-hole subband H2 with nonmonotonic dispersion law [13,14].…”

“…The highest valence band is now the second size-quantized heavy-hole subband H2 with nonmonotonic dispersion law [13,14].…”

Tunneling studies of two-dimensional states in semiconductors with inverted band structure: Spin-orbit splitting and resonant broadening

“…It was shown in a number of theoretical and experimental articles [2][3][4][5][6][7][8] that these states play a key part in forming the energy spectrum of 2D states in heterostructures and superlattices based on inverted semiconductors.…”