Surface Acoustic Waves in DC Fields

The contactless Surface Acoustic Wave (SAW) technique is implemented to probe the high-frequency conductivity in low dimensional (2D) structures, by measuring the SAW attenuation and velocity.

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.

Images

Click on images to view a larger version or to download.

Instrumentation

  • Compatible Magnets

  • Compatible Sample Environments

  • Available Equipment

Resistive Magnets

Superconducting Magnets

  • 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)

Related Publications

I.L. Drichko et al., Electronic band structure in n-type GaAs/AlGaAs wide quantum wells in tilted magnetic field, Journal of Physics-Condensed Matter, 32, 3, 035303 (2020) Read online 


I.L. Drichko et al., Composite fermions in a wide quantum well in the vicinity of the filling factor 1/2, Solid State Communications, 301, 113698 (2019) Read online 


I.L. Drichko et al., Intersubband scattering in n-GaAs/AlGaAs wide quantum wells, Physical Review B, 97, 075427 (2018) Read online 


I.L. Drichko et al., Melting of Wigner crystal in high-mobility n-GaAs/AlGaAs heterostructures at filling factors 0.18>n>0.125: Acoustic studies, Physical Review B, 94, 7, 075420 (2016) Read online 

Staff Contact

Last modified on 24 February 2021