Extended Data Fig. 1: Details of the growth structure. | Nature

Extended Data Fig. 1: Details of the growth structure.

From: Observation of half-integer thermal Hall conductance

Extended Data Fig. 1

Schematic of the conduction band in the MBE-grown structures that were studied. The SPSL doping scheme comprises δ–Si doping planes placed in narrow GaAs quantum wells (QW). The thickness of the GaAs and AlAs quantum wells in SPSL is chosen in such a way that the X-band minima of the AlAs layers reside below the Γ-band minimum of the GaAs. Electrons that spill over to the AlAs wells have low mobility and thus do not participate effectively in the conduction process. This structure suffers from substantial added bulk heat conductance. The structure used in our study, with δ–Si doping in low-Al-mole-fraction AlGaAs, did not have a visible bulk thermal conductance.

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