Scanning tunneling microscope measurements of the amplitude of vibration of a quartz crystal oscillator

Borovsky, Brian; Mason, B. L.; Krim, J.

doi:10.1063/1.1289235

Cited by 110 publications

(53 citation statements)

References 11 publications

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“…The typical excitation voltage V of the QCM was 0.6 mV, of which the vibrational amplitude A was estimated to be 0.03 nm at 140 MHz from the relation A / QV=n 2 . 11,12) In the present experiments, we observed no nonlinear dependence on V between 0.2 and 0.6 mV. The inverse quality factor change ÁQ À1 was obtained from the change in resonance voltage.…”

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confidence: 77%

Extremely High Frequency Dependence of Two-Dimensional Superfluid Onset

et al. 2009

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We observed the frequency dependence of the superfluid transition of 4 He films adsorbed on planar gold up to a very high frequency of 180 MHz, using the overtone harmonic modes of a quartz crystal microbalance. The superfluid onset was observed at a temperature markedly higher than the KosterlitzThouless (KT) transition temperature, the onset temperature in the low-frequency limit. The observed frequency dependence is surprisingly well reproduced by the dynamic theory close to the high-frequency condition where the vortex diffusion length in a period becomes as small as the vortex core diameter. We also observed that the superfluid vortex parameters depend strongly on the kind of substrate as well as on 4 He film thickness. KEYWORDS: KT transition,4 He film, superfluidity DOI: 10.1143/JPSJ.78.033604The superfluid onset of two-dimensional (2D)4 He films observed using a torsional oscillator at 1.2 kHz 1) was understood in the framework of the Kosterlitz-Thouless (KT) transition, 2) which is completely different from the Ginzburg-Landau (GL)-type phase transition. The KT transition is now a general concept for superconducting films,3) Josephson-junction arrays, 4) and the Bose-Einstein condensation of a 2D atomic Bose gas.5) The KT transition temperature T KT is far below the GL temperature T GL . The KT theory predicts that the observed superfluid onset close to T KT is determined by the pairing/unbinding of superfluid vortices. However, the actual important properties of the vortices, e.g., the vortex core diameter a 0 and the vortex diffusion constant D, have not been obtained precisely even for typical (standard) 2D4 He films. Furthermore, the KT context for the 4 He films would definitely break down under some extreme conditions of the film geometry formed in pores and of the high frequency in the measurement.For 4 He films formed in porous media such as Vycor glasses, Minoguchi and Nagaoka 6) calculated that the superfluid onset temperature becomes higher than T KT and that the onset temperature diverges with a decrease in the pore diameter to the core diameter a 0 . Therefore, the context breaks down for 4 He films formed in nanopores whose diameter is equal to or smaller than a 0 . Recently, superfluidity was observed for 4 He films formed in 1D nanopores larger than 1.8 nm in diameter.7) Its superfluid onset should be considered in another context, because the smallest superfluid tube diameter was estimated to be about 1 nm, which is smaller than a 0 ¼ 2:5 AE 1:2 nm, estimated earlier for the Vycor glasses. 8)According to the dynamic KT theory, 9) the superfluid onset depends on the measuring frequency !=2. The observed superfluid density s is equal to a stiffness at the size of the vortex diffusion length r D ¼ ffiffiffiffiffiffiffiffiffiffiffiffiffiffi 14D=! p in the period 1=!. At a low frequency limit (i.e., r D ! 1), s shows a universal jump at T KT . At a finite frequency, the superfluid onset occurs at a temperature slightly higher than T KT , where r D becomes equal to the 2D phase coherence leng...

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confidence: 77%

Extremely High Frequency Dependence of Two-Dimensional Superfluid Onset

et al. 2009

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“…, where d V is the drive voltage, Q is the quality factor of the oscillator and v k is the electromechanical coupling constant, which for an AT-cut TSM quartz oscillator is 1.4 pm/V (Borovsky et al 2000). …”

Section: Methodsmentioning

confidence: 99%

Probing biomolecular interaction forces using an anharmonic acoustic technique for selective detection of bacterial spores

Ghosh

Ostanin

Johnson

et al. 2011

Biosensors and Bioelectronics

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“…The crystals were driven with a Clapp feedback oscillator circuit, 25 and the resonant frequency and amplitude 26 were monitored with a frequency counter and an oscilloscope, respectively. The quality factors of the resonators were measured with a simple ''ring-down'' technique 27 and were near 10 5 . Two probes were used, a fused silica sphere ͑Duke Scientific, Palo Alto, CA͒, 0.5 mm radius, and an etched tungsten wire, ϳ12 m tip radius.…”

Section: Methodsmentioning

confidence: 99%

“…The model we have described assumes the contact regions do not slip. Equation ͑8͒ shows that for a shear modulus of about 10 GPa, QCM oscillation amplitude u 0 ϳ10 nm ͑a typical value for the QCM's in these experiments͒, 27 and ⑀ϳ100 nm, the shear stresses applied to the interface may extend into the GPa range, enough to cause significant plastic deformation and wear. Indeed, a transfer film was observed, apparently of silver from the electrode surface, on the silica sphere after the experiments.…”

Section: Modelingmentioning

confidence: 99%

Measuring nanomechanical properties of a dynamic contact using an indenter probe and quartz crystal microbalance

Borovsky

Krim

Asif

et al. 2001

Journal of Applied Physics

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A study of the contact mechanics of a probe tip interacting with a quartz crystal microbalance ͑QCM͒ has been performed, involving simultaneous measurements of normal load, displacement, and contact stiffness with changes in QCM resonant frequency. For metal-metal and glass-metal contacts in air, the QCM frequency shifts were observed to be positive, and directly proportional to the contact area as inferred from the contact stiffness. Interfacial characteristics of the probe-tip contact ͑elasticity, contact size, and an estimate of the number of contacting asperities͒ were deduced by extending a prior model of single asperity contact to the case of multiple contacts. The extended model clarifies a number of seemingly disparate experimental results that have been reported in the literature.

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Scanning tunneling microscope measurements of the amplitude of vibration of a quartz crystal oscillator

Cited by 110 publications

References 11 publications

Extremely High Frequency Dependence of Two-Dimensional Superfluid Onset

Extremely High Frequency Dependence of Two-Dimensional Superfluid Onset

Probing biomolecular interaction forces using an anharmonic acoustic technique for selective detection of bacterial spores

Measuring nanomechanical properties of a dynamic contact using an indenter probe and quartz crystal microbalance

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