Contactless Measurement of AC Conductance in Quantum Hall Structures

Abstract

We report a procedure to determine the frequency-dependent conductance of quantum Hall structures in a broad frequency domain. The procedure is based on the combination of two known probeless methods -- acoustic spectroscopy and microwave spectroscopy. By using the acoustic spectroscopy, we study the low-frequency attenuation and phase shift of a surface acoustic wave in a piezoelectric crystal in the vicinity of the electron (hole) layer. The electronic contribution is resolved using its dependence on a transverse magnetic field. At high frequencies, we study the attenuation of an electromagnetic wave in a coplanar waveguide. To quantitatively calibrate these data, we use the fact that in the quantum-Hall-effect regime the conductance at the maxima of its magnetic field dependence is determined by extended states. Therefore, it should be frequency independent in a broad frequency domain. The procedure is verified by studies of a well-characterized $p$-SiGe/Ge/SiGe heterostructure.

7 pages, 8 figures; to be submitted to JAP

References in corpus (3)

• Commensurability oscillations in the rf conductivity of unidirectional lateral superlattices: measurement of anisotropic conductivity by coplanar waveguide
• Magnetotransport in low-density $p$-Si/SiGe heterostructures: From metal through hopping insulator to Wigner glass
• Acoustoelectric effects in very high-mobility $p$-SiGe/Ge/SiGe heterostructure at low temperatures in high magnetic fields

Cited by in corpus (5)

• Crossover between localized states and pinned Wigner crystal in high-mobility n-GaAs/AlGaAs heterostructures near filling factor $\nu =1$
• Wigner crystal in a two-dimensional electron system in the vicinity of filling factor 1/5: Acoustic studies
• AC and DC Conductivities in an n-GaAs/AlAs Heterostructure with a Wide Quantum Well in the Integer Quantum Hall Effect Regime
• Universal Frequency Dependence of the Hopping AC Conductance in p-Ge/GeSi Structures in the Integer Quantum Hall Effect Regime
• Resistively loaded coplanar waveguide for microwave measurements of induced carriers