Stm Definition and 29 Threads

In an STM, you image the surface topography by tunnelling electrons from the metallic tip to the conductive surface, while measuring the current. I have worked with these instruments before and I never understood why does one need a quantum explanation for this. Wouldn't the electron jump to...

I know that scanning tunneling microscopy (STM) I-V curve is exponential for a conducting sample. How would it look like if I had a semiconductor and a non-conductor sample?

Homework Statement Suppose the STM tip current is given by i = aV e^{-A\phi^{1/2}s} a) Derive an expression for the fractional change in tip current as function of fractional change in tip spacing s. b) If \phi = 4V select a reasonable set of V values so that a 1Å increase in s will cause...

most STM images of graphite have been acquired using a bias voltage of ? Or in the range ? Same thing for graphene and Silicon carbide

This effect can be seen in the short film "A Boy and His Atom". I had a couple ideas about what this could be but I am curious if someone knows better.

Hi again people! So if I have two STS (scanning tunneling spectroscopy) spectra, one taken on a substrate and the other one taken on an adsorbate layer ontop of the substrate. Assuming there is some sort of interfacial dipole that forms between the substrate and the adsorbate layer, can I...

Hi there people! So my question is why you can see localized surface states within the band gap of the material with an STM. How is a tunneling circuit being established?

when physicists say that they apply voltage to the tip or the sample, do they mean that the tip or sample become electrically charged?

Hello everyone, I just started learning Matlab and I am trying to figure out how to image analyze an STM file. Where do I begin? Thank you, Michelle

Here we have a STM tip placing a potential V across a monolayer with a single electron on it. | STM (scanning tunneling microscope) Tip | | |...

hi, I've got a really great picture of the carbon atoms in a graphine (HOPG) sample, using STM technique (picture attached). I would like to remove from the picture all the data came from noise etc.. I'm working with MATLAB, and I tried to use fast Fourier transform (fft2), but didn't know how...

Homework Statement Suppose that an STM scans a surface at a distance of a=1.000nm. Take the height of the potential barrier to be U°-E=2.00 eV. If the STM tip movies away from the surface by 2.00%, estimate the percentage change in the tunneling current. Homework Equations The...

Homework Statement In my never ending quest to suck and never be able to do Taylor Expansions, I have another one. I hope one day I'll be able to do these. I have an unknown material and a scanning tunnel microscope. A layer of hydrogen atoms of radius R are added to the surface. This of...

Hey there, I'm pursuing a degree in Msc. Nanoscale science, and I've been studying about Scanning tunneling microsopes that use Quantum tunneling to study the surface struture of materials. My question is: What is the maximum distance between the surface that's been studied, and the STM tip...

Do they just add waves into demonstrate the probability wave? They could not be detecting the electron in more than one place. Is it because they make so many measurements to generate the image that the amplitudes you see are a collection of each measurement? A good example is the copper...

I've finished a lab with Scanning Tunneling Microscopy in an upper level physics undergrad course, and now I have about 50 ".ezd" files to analyze. They were produced with the Nanosurf easyScan microscope, which I'm told is quite common in very basic applications. I'm looking for some...

I've recently started trying to use this technique, but I've had some difficulties I can't figure out how to overcome. We make our own probe tips from a very small length of 30 gauge wire, and they seem to be of decent quality. We've tried to image a layer of graphite, a gold surface...

Hi, I'm an undergrad getting my first taste of STM. I'm hoping somebody can give me some insight into the following: I'm wondering why graphite doesn't form a surface reconstructon. I know gold does to minimize tensile strain... I am wondering why this doesn't happen in graphite.

Any suggestions how I can improve the quality of STM (scanning tunneling microscopy) images? And how can I trace artifacts?

How on Earth do 'they' get a probe that close to a sample in SPM without it touching (in STM) or at just the right controlled amount?

''The Scanning Tunnelling Microscope probes the density of states of a material''... What does this actually mean?

Hi, I'm working on a UHV STM. Recently I opened the multigain switch to set higher gains and I also changed the bandwidth. In the manual I read that the bandfilter is a so called 'single pole filter' and has a 6dB/Octave roll off. Can someone help me to understand what a single pole...

Hi, I'm building a STM, and this is the circuit I use : http://www.geocities.com/spm_stm/Simple_STM_Rev_C.PDF I'm right now testing the circuit I build. I build a small part (U3A), and then test it, and build another small part (U3B) and test, then connect the two and test it again...

Hi, for my integration class I am building a scanning tunnelling microscope (STM). I found some interesting designs and I choose the cheapest one (students are poor) witch uses a unimorph disk. Here is the STM design I plan to build: http://www.geocities.com/spm_stm/". For my class I need to...

Hi, for my integration class I am building a scanning tunnelling microscope (STM). I found some interesting designs and I choose the cheapest one (students are poor) witch uses a unimorph disk. The circuits are not that hard to build but I also need to understand them. I have some knowledge in...

What are the environmental conditions necessary for the operation of an STM and an AFM?

hi to everyone! who can help me with a almost and understandable complete theory of Scanning tunneling Microscopy technique? with my best wishes O.

does anyone have a link or a formula for calculating the resolution of a STM based on the tip size.

Hello everyone! I have a little question about STM. Why can we move atoms with STM by increasing the tunneling current?