Sunday, May 10, 2020

Brief items

Apologies for the slowed frequency of posting.  Academic and research duties have been eating a lot of bandwidth.  Here are a few items that may be of interest:

  • This article about Shoucheng Zhang is informative, but at the same time very sad.  Any geopolitics aside, he was an intense, driven person who put enormous pressure on himself.  It says something about self-perception under depression that he was concerned that he was somehow not being recognized.  
  • This paper caught my eye.  If you want to see whether there is some dependence of electronic conduction on the relative directions of a material's crystal axes and the current, it makes sense to fabricate a series of devices oriented in different directions.  These authors take a single epitaxial film of a material (in this case the unconventional superconductor Sr2RuO4) and carve it into a radial array of differently oriented strips of material with measurement electrodes.   They find that there do seem to be "easy" and "hard" directions for transport in the normal state that don't have an obvious relationship to the crystal symmetry directions.  A similar approach was taken here in a cuprate superconductor.  
  • I like the idea of making characterization tools broadly available for low cost - it's great for the developing world and potentially for use in public secondary education.  This work shows plans for a readily producible optical microscope that can have digital imaging, motorized sample positioning, and focusing for a couple of hundred dollars.  Fancier than the foldscope, but still very cool.  Time to think more about how someone could make a $100 electron microscope....
  • Here is a nice review article from the beginning of the year about spin liquids.
  • I was going to point out this article about ultralow temperature nanoelectronics back in March, but the pandemic distracted me.  From grad school I have a history in this area, and the progress is nice to see.  The technical challenges of truly getting electrons cold are formidable.


Anonymous said...

Regarding cheap electron microscopes (which are *long* overdue), you may be interested in AweSEM from the group of Alireza Nojeh at UBC

Anonymous said...

I really hope the tragic case of the late SC Zhang shows scientists that supporting mental health isn't just about fulfilling requirements from HR, it has real impact and consequences on the health of science overall.

Douglas Natelson said...

Anon@5:11, that's very much what I was vaguely thinking about - have they actually built a demo? I think you have serious challenges positioning the very fragile "electron transparent membrane" close enough to a sample surface to catch the secondary electrons with good yield. (I mean, you could do the positioning in a clean environment with ultrafine motor control and positioning, but could you do it cheaply and easily?)

Anon@6:48, absolutely. The stigma that still lingers about asking for help for mental well-being is strong in many high-drive fields like science. I've known people who don't even talk about being concerned about grants or papers because of fear of being perceived as "weak". That's not a healthy.

Anonymous said...

I recall there was a prototype but I can't find a publication about it st the moment. The mean free path of 40keV electrons in air is upwards of 0.5mm, so I don't think it's as drastic as it might appear.

Some details are given in this patent:

Looks like Manu Prakash is involved too.

Anonymous said...

I need advice from professor's here.

I work as a postdoc since May 2018 in an established lab with a competitive PI who has a good body of work in high impact journals like Advanced Materials, Nanoletters, ACS photonics, ACS applied materials, PRL etc. My work is experimental in nature where I mostly do AFM, Raman, PL and transmission spectroscopy for 2D TMD based metasurfaces fabricated on transparent substrates. Probably by end of the year I will have 2-3 1st author publications in journals with IF 7 or above. My contract was till May and now has been extended till November.

In the meantime I was searching for positions in other labs and recently I won a competition for a project from a young PI that involves work on 2D TMDs or metal monochalcogenides. This will involve mechanical exfoliation, reflection contrast microscopy, magnetic field and temperature dependent investigations (Raman and PL) of various heterostructure configurations. This ll be new for me and the position is for 2 years. However, recently my current PI told me that he has a new project approved and can support me for another 2 years but without any increase in pay. Probably I'll get to work on optical related effects and biosensing using 2D TMDs. The salary for the new position is also similar to the current one and the lab is situated in a different country. The PI there is a young guy with publications in PRL, Sci. Reports, npj 2D materials, also multi author ones in Nature journals.

I am in a fix what to do. Shall I move or not? what aspects I need to consider? I shall be grateful if senior people can advise me.

Douglas Natelson said...

Anon@2:17, all things considered these days, that's not an unenviable position - two jobs to choose from. I presume from context here that your desired end point is as a professor at a research university. Given that the new position would involve changing countries, I would think that has to be a major factor in your decision-making. International travel and immigration is complicated right now (and the situation in the US is unlikely to get simpler for some time). One thing to consider is whether the change in location would really let you expand your skill set and work on projects that you think are exciting and higher impact than what you're likely to do if you stay in place. High impact pieces of work that you and the PI mentor can really call your own are valuable currency for later pursuits. (For what it's worth, intuition is not a bad guide - your brain does a lot of background processing. If one of the choices feels better somehow, it's worth considering.) Good luck in your decision.

Anonymous said...

@Anon 2:17 PM. If your pursuit for academia does not work out and you are forced to look for jobs in industry or banking, are there more opportunities for you in the country where you currently are or in the country that you would move to if you took the job with the young PI? I did my PhD in the US and I know several people who came to the US for postdocs for job reasons. Of course, under this current US administration, hoping to get jobs in the US might not be viable but for example, there would be more industrial jobs available in Germany than in Spain.

Anonymous said...

Dear Prof. Natelson,

Thank you for your advice. I am still thinking over it. I shall need to discuss more with the younger PI about the project as it is more in-depth physics (studying electronic bandstructure of 2D TMDs), considering what I do now (large area nanophotonics). I like the prospect, but to move from a material science environment (both in my Phd and current postdoc) to deep physics is one issue that I probably need to consider, although I have my bachelor's and master's in Physics.

@Anon 3:45 PM, very slim chances of me getting a job in the current country. I am not able to find position even in R&D of a company as there are very few offers. Unemployment rate is quite high if I compare it to the country that I have the chance to move to.

Anonymous said...

Strange things are going on.