D. Nano-Electro-Mechanical Systems (NEMS)
Nanomechanics features three-dimensional nanostructuring, which allows full exploitation of the mechanical degree of freedom on the nanometre scale. An introduction to the underlying mechanics is given and finite element methods required for simulations are discussed. Further topics presented include measurement methods for probing the mechanical properties of free standing nanowires, sensor applications and nonlinear properties of nanomechanical resonators. Other applications such as parametric frequency tuning are demonstrated and the major sources of dissipation are discussed.
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Nanomechanical Electron Transport
D. V. Scheible, A. Erbe, and R. H. Blick -
Mechanical gating of coupled nanoresonators
Laura Pescini, Bert Lorenz, Robert H. Blick -
Broadband acoustic tuning of nanomechanical resonators
Florian W. Beil, A. Wixforth and Robert H. Blick.
in cooperation with Max Bichler and Werner Wegscheider.
Nanomechanical Electron Transport
D. V. Scheible, A. Erbe, and R. H. Blick
The integration of nano-mechanical and nano-electronic systems promises very appealing applications in mesoscopic physics, ranging from current standard devices to detectors of ultra-weak forces. The concept of the quantum bell - a mechanically oscillating single electron island [1] - has been extended recently [2], including new driving methods and broader access to experimental parameters. Fig. 1 shows an excerpt of the device and the schematic testing setup, as well as the frequency-dependent current across the structure, being characteristic for resonant mechanical electron transporters. In addition to this, nano-mechanical electron shuttles also gain an increasing interest from the theoretical viewpoint [3].
- A Erbe, Ch Weiss, W Zwerger, and R H Blick, Phys. Rev. Lett. 87, 096106 (2001).
- D V Scheible, A Erbe, and R H Blick, New J. Phys. 4, 86.1 (2002).
- M Jonson and R Shekhter, Phys. World 16, 21 (2003).
Mechanical gating of coupled nanoresonators
Laura Pescini, Bert Lorenz, Robert H. Blick
We study the mechanical properties of suspended Au/Si nanostructures with focus on the interaction between mechanical nanoresonators operating in the rf regime. The actuation of the beams and their displacement detection is performed magnetomotively. The driving force is the Lorentz force which acts on the suspended device when an alternate current flows in the device and an orthogonal magnetic field is present. We find that the electromechanical coupling between two resonators allows to use one of them to effectively tune the frequency of the other. The deformation of the eigenmodes leads in fact to high frequency modulation of the capacitive coupling between the wires. This can be expressed by an additional term in the driving force, Fc(t)=C(t)V2(t)/d(t), where C(t), V(t) and d(t) are respectively the time dependent capacitance, potential difference and separation between the two wires [1].
- L. Pescini, H. Lorenz, and R.H. Blick, Appl. Phys. Lett. 82, 352 (2003).
Broadband acoustic tuning of nanomechanical resonators
Florian W. Beil, A. Wixforth and Robert H. Blick
in cooperation with Max Bichler and Werner Wegscheider.
For a variety of applications in integrated communication and sensor devices nano-electromechanical systems (NEMS) present a new generation of high frequency components. Up to now conventional excitation mechanisms for NEMS are based either on high magnetic (magnetomotive method) or electric (electromotive method) fields which limits the use of NEMS. We present experiments utilizing a surface acoustic wave (SAW) transducer on GaAs to excite nanomechanical resonators operating at frequencies up to 300 MHz. We show that via SAW full control over the fundamental properties of the resonator is achieved [1]. The quality factor of the mechanical resonance can be tuned over an order of magnitude, while by pulsed acoustic excitation an increased quality factor can be achieved. As acoustic tuning of internal damping mechanisms in the nano resonators is feasable, it is possible to determine the friction mechanisms [2] active on the nanometer scale.
- F. W. Beil, A. Wixforth and R. H. Blick, IEEE Sensors (2002).
- F. W. Beil, A. Wixforth and R. H. Blick, to be published.