Skip to main content

Graphene : Elasticity meets electronics on atom-thin membranes

The speaker at the physics colloquium this week was Prof. Manu Jaiswal from the Dept. of Physics, IITM and his talk was about graphene, exciting research on the elasticity of graphene coatings/layers and on the recent developments in the field.

The talk started off with Zidane's penalty kick of the football world cup and at the end, he pointed out how the shape of the goal net has changed. He mentioned that physicist and mechanical engineers aren't the only people working on material elasticity, so are footballers, so to speak. The goal net design changed in 2002 from being a square net to a hexagonal net. It was shown, through simulations, how stress propagates along the two structures and how hexagonal structures behave like a 2D isotropic body where as square nets have local minima along the grid outlines.

Moving on the talk, he mentioned how he himself got involved in understanding the elasticity of graphene. As is the case with many-a-stories in science, results that couldn't be explained from earlier experiments were what pushed him to ask questions about elasticity of graphene. He talked about how studying the variation of resistivity of graphene layers on SrTiO3 with temperature helped them understand that a change in the morphology of the substrate on which graphene is grown can lead to a change in the resistivity of the graphene layer above. They explored this idea further by developing micro hydrogels. To be put simply, hydrogels are those that grow in size upon absorption of water. Similarly, in their lab, they worked on developing a structure of micro hydrogels that would grow in size upon hydration. The graphene layer would be deposited pre-hydration and it would be studied post-hydration, the effects of shear stress on the conductivity and effects, if any, when the graphene layer is completely detached (delaminated) from the substrate at certain regions. Think of a tent, held up by poles on all four sides and covered by a tarp. Now think of what will happen if the poles grow in size but the size of the tarp remains the same! Now imagine a thousand poles and a large tarp, where the poles are the micro hydrogels and the tarp or the covering is the graphene layer. He talked about theoretical and experimental results as to how the resistivity of the graphene layer changes during this process. He concluded his talk by talking about graphene origami electronics where graphene sheets would be bent, twisted and strained at will to create directional conductivity, to be used as processing elements or chips. I have skipped quite a few things that he talked about but well, this is the part that I understood and that I could follow.

Popular posts from this blog

Animation using GNUPlot

Animation using GNUPlotI've been trying to create an animation depicting a quasar spectrum moving across the 5 SDSS pass bands with respect to redshift. It is important to visualise what emission lines are moving in and out of bands to be able to understand the color-redshift plots and the changes in it.
I've tried doing this using the animate function in matplotlib, python but i wasn't able to make it work - meaning i worked on it for a couple of days and then i gave up, not having found solutions for my problems on the internet.
And then i came across this site, where the gunn-peterson trough and the lyman alpha forest have been depicted - in a beautiful manner. And this got me interested in using js and d3 to do the animations and make it dynamic - using sliders etc.
In the meanwhile, i thought i'd look up and see if there was a way to create animations in gnuplot and whoopdedoo, what do i find but nirvana!

In the image, you see 5 static curves and one dynam…

on MOOCs.

For those of you who don't know, MOOC stands for Massively Open Online Course.

The internet is an awesome thing. It's making education free for all. Well, mostly free. But it's surprising at the width and depth of courses being offered online. And it looks like they are also having an impact on students, especially those from universities that are not top ranked. Students in all parts of the world can now get a first class education experience, thanks to courses offered by Stanford, MIT, Caltech, etc.

I'm talking about MOOCs because one of my new year resolutions is to take online courses, atleast 2 per semester (6 months). And I've chosen the following two courses on edX - Analyzing Big Data with Microsoft R Server and Data Science Essentials for now. I looked at courses on Coursera but I couldn't find any which was worthy and free. There are a lot more MOOC providers out there but let's start here. And I feel like the two courses are relevant to where I …

Pandas download statistics, PyPI and Google BigQuery - Daily downloads and downloads by latest version

Inspired by this blog post :, I wanted to play around with Google BigQuery myself. And the blog post is pretty awesome because it has sample queries. I mix and matched the examples mentioned on the blog post, intent on answering two questions - 
1. How many people download the Pandas library on a daily basis? Actually, if you think about it, it's more of a question of how many times was the pandas library downloaded in a single day, because the same person could've downloaded multiple times. Or a bot could've.
This was just a fun first query/question.
2. What is the adoption rate of different versions of the Pandas library? You might have come across similar graphs which show the adoption rate of various versions of Windows.
Answering this question is actually important because the developers should have an idea of what the most popular versions are, see whether or not users are adopting new features/changes they provide…