Dresden 2020 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 33: Optical properties
HL 33.3: Talk
Tuesday, March 17, 2020, 14:30–14:45, POT 112
Optical Tuning between the Trivial and Topological Regime of InAs/GaSb Quantum Wells — •Manuel Meyer1, Sebastian Schmid1, Gerald Bastard2, Fabian Hartmann1, and Sven Höfling1 — 1Technische Physik, Physikalisches Institut and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, Am Hubland 97074 Würzburg, Germany — 2Département de Physique, Ecole Normale Supérieure de Paris, 75005 Paris, France
Topological Insulators (TI) are a state of matter characterized by an insulating bulk and gapless helical edge states which were first demonstrated on HgTe/CdTe heterostructures[1]. The proposed TI based on composite InAs/GaSb heterostructures are especially appealing due their rich phase diagram that can be accessed via controlling external electrical fields[2]. We present another tuning knob of the phase diagram in InAs/GaSb quantum wells via optical excitation. Under constant illumination the majority charge carrier type switches from electrons to holes. At an intermediate value of illumination time both carrier types are present, indicating electron-hole hybridization[3]. Magnetic fields applied parallel to the surface enable us to determine the topological insulating phase. The optical tuning is caused by the negative persistent photoconductivity of antimonides in combination with a persistent charge carrier accumulation. This paves the way to an optical control of the phase diagramm of InAs/GaSb heterostructures.
[1] M. König et al., Science 318, 766 (2007).
[2] F. Qu et al., Phys. Rev. Lett. 115, 036803 (2015).
[3] G. Knebl et al., Phys. Rev. B 98, 041301(R) (2018).