Observation of a local dipole moment of Si atoms on Si(100) surfaces using Non-contact Scanning Nonlinear Dielectric Microscopy

2008 ◽  
Author(s):  
Nobuhiro Kin ◽  
Yuhei Osa ◽  
Yasuo Cho
Keyword(s):  
Dipole Moment ◽  
Nonlinear Dielectric

On the theory of the nonlinear effect in polar liquids

1978 ◽  
Vol 56 (2) ◽  
pp. 216-225 ◽  
Author(s):  
Constantino Grosse ◽  
Pedro Brito
Keyword(s):  
Dipole Moment ◽  
Nonlinear Effect ◽  
Spherical Cavity ◽  
Applied Field ◽  
Polar Liquids ◽  
Nonlinear Dielectric ◽  
Average Value ◽  
Molecular Moment ◽  
Dipolar Potential ◽  
Weak Fields

It is shown that in order to relate the permittivity ε = ε0[1–λE2] of a nonlinear dielectric with molecular parameters using Onsager's formalism, the condition to be used is that the average value of the dipolar potential outside the cavity and with an applied field must vanish. Consequently, the potential for a rigid dipole in a spherical cavity filled up with a continuum ε∞ and surrounded by a nonlinear dielectric immersed in a strong applied field are calculated both inside and outside. The average value of the external dipole moment is deduced from the torque exerted by the field outside the cavity on the sources of the applied field.The expression thus obtained for the parameter λ leads to values that are always positive and slightly smaller than those corresponding to earlier studies. The expression deduced for the permittivity in weak fields ε0 introduces a correction to Onsager's equation consisting of a factor multiplying the square of the molecular moment. In contradiction with recent results by other authors, this factor is always less than 1 and its value is of the order of 0.9.

Simultaneous Observation of Surface Morphology and Dielectric Properties Using Non-Contact Scanning Nonlinear Dielectric Microscopy with Atomic Resolution

2006 ◽  
Vol 966 ◽  
Author(s):  
Ryusuke Hirose ◽  
Yasuo Cho
Keyword(s):  
Dielectric Constant ◽  
Dipole Moment ◽  
Tunneling Current ◽  
Atomic Resolution ◽  
Control Technique ◽  
Simultaneous Observation ◽  
Nonlinear Dielectric ◽  
Height Control ◽  
Moment Distribution ◽  
Microscopy Techniques

ABSTRACTRecently, we have developed Non-Contact Scanning Nonlinear Dielectric Microscopy (NC-SNDM) with a new height-control technique utilizing higher order nonlinear dielectric constant detection (ε(4) signal). In theoretically, NC-SNDM has quite high height sensitivity against the gap between tip and sample as well as STM technique and the simultaneous observation of the topography and ferroelectric polarization (local dipole moment) distribution with atomic resolution has been expected. To confirm such performance of NC-SNDM with atomic resolution, UHV-SNDM was developed and Si(111) cleaned surface was chosen as a specimen. As a result, we have succeeded in observing Si(111) 7×7 atomic structure. Moreover, distribution of tunneling current and lowest order nonlinear dielectric signal ε(3) could be observed simultaneously. To the best our knowledge, this is the first successful demonstration of the atomic resolution achievement in dielectric microscopy techniques.

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