A SAW is excited on a side of a piezoelectric platelet (LiNbO3) by an inter-digital transducer. The SAW propagating along the plane of lithium niobate is accompanied by a high-frequency electric field. This electric field penetrates into the 2D channel located in the semiconductor structure placed on the surface. The field produces electrical currents, which, in turn, cause Joule losses. As a result of the interaction of the SAW electric field with charge carriers, the SAW attenuation and its velocity shift are governed by the complex high-frequency conductivity, σhf(ω) . Therefore, the real and imaginary parts of the conductivity could be calculated from the SAW attenuation and velocity measured in the experiment. This “sandwich"-like experimental configuration enables contactless acoustoelectric experiments on non-piezoelectric 2D systems, for example built from Si and Ge.
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- Lithium Niobate plate (about 12x5mm2) with two interdigital transducers mounted on a sample holder. Lithium Niobate plate (about 12x5mm2) with two interdigital transducers mounted on a sample holder.
- Sketch of sample mounting (upside down) between two interdigital transducers. Sketch of sample mounting (upside down) between two interdigital transducers.
- Signal Generator Agilent E4424B
- Signal Generator Agilent E8257D
- Signal Generator Agilent N5171B
- Signal Generator Stanford Research Systems SG382
- Function generator Stanford Research Systems DS345
- Digital Delay / Pulse generator DG535
- Gated Integrator & Boxcar Averager SR250
- Preamplifier SR240
- Colby Instrument Programmable Delay Line PDL-100A-100n
- Oscilloscope Tektronix TDG3034B
- Oscilloscope LeCroy HDO4054
- Homemade two channel (Amplitude & Phase) RF detector (30 – 2700 MHz)
I. L. Drichko, et al, Acoustoelectric effects in very high-mobility p-SiGe/Ge/SiGe heterostructure at low temperatures in high magnetic fields, J. Appl. Phys. 114 (2013) Read online
I.L. Drichko, et al, Acoustic studies of ac conductivity mechanisms in n-GaAs/AlxGa1-xAs in the integer and fractional quantum Hall effect regime, Phys. Rev. B 83 (2011) Read online
I. L. Drichko, et al, Magnetotransport in low-density p-Si/SiGe heterostructures: From metal through hopping insulator to Wigner glass, Physical Review B, 77 (2008) Read online