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Electron band structure in germanium, my ass (2000)

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Re: Electron band structure in germanium, my ass (2000)

#71

Post by pbmonster »

splittingTimes wrote: post #5

Exactly my experience back in the days doing the mandatory "advanced experimental physics laboratory semester" where you had to do like 14 vastly different experiment of the caliber described in that post in the course of one semester on old equipment that would break during the experiment, with less than motivated PhD students or post grads as teachers. Of the 14 experiments only two worked and we got the expected r…

> one semester on old equipment that would break during the experiment

I saw that as a learning opportunity, teaches you which glues are cryo-proof, how to switch fuses on amplifiers (and other, more complicated electronics quick-fixes), and how important knowing people to borrow equipment from is.

Unless your lab is swimming in money, those are valuable skills for an experimentalist. And even if you swim in money, buying fancy new stuff has a minimum 8 week lead time while walking down the hall to the correct shelf to pilfer takes 5 minutes and gets you results before lunch.

> with less than motivated PhD students or post grads as teachers

This is an unfortunate truth everywhere I taught. Unfortunately, teaching the same thing 14 times a semester is no fun, and every single person who enjoys teaching (and is good at it) knows it, and instead teaches any available lecture, seminar, tutorial or exercise - anything, where you get to teach something new every week and that allows you to stay with the same students for longer.

Re: Electron band structure in germanium, my ass (2000)

#72

Post by EVa5I7bHFq9mnYK »

madengr wrote: post #4

You sure it isn’t Schottky diodes formed by the metallic contacts that are interfering with the measurement of the bulk germanium properties? I’d sputter deposit metallic contact regions and solder to those, then maybe compare two different thickness samples and look at the difference in resistivity vs. temperature, essentially de-embedding your fixture.

Could they measure the resistance in two direction, then subtract one from another to isolate the symmetric part?

Re: Electron band structure in germanium, my ass (2000)

#73

Post by cyberax »

onetimeuse92304 wrote: post #70
EVa5I7bHFq9mnYK wrote: post #68

>> Going into physics was the biggest mistake of my life. I should've declared CS. I still wouldn't have any women, but at least I'd be rolling in cash. Hahaha, gold. I made that realization in the middle of my PhD and switched (40 years ago). Not regretting a moment. What broke me was the amount of politics you must engage in.

I was 3rd semester into theoretical math in 1999. Got a job on a side as a tech support. Then realised I am earning more in an entry level tech job than I can ever hope to earn in math. Did my 2 + 2 and went tech with no hesitation.

Applied math major here. It's practically CS anyway!

Re: Electron band structure in germanium, my ass (2000)

#74

Post by phtrivier »

mensetmanusman wrote: post #44
phtrivier wrote: post #20

Earlier quoted context omitted.

The double irony would be for the author to have persevered in physics and now hold several patents over solid state batteries that are going to revolutionize society and fix climate change, while their CS major friends just got fired by some GAFAM for not getting enough minimum-pay workers to click on funny cat memes.

Even if true the CS students would still be ahead earnings wise. /source I went into physics/materials

Let's make it "triple irony", then, I suppose ?

Re: Electron band structure in germanium, my ass (2000)

#75

Post by lonelyasacloud »

evilotto wrote: post #49
spxtr wrote: post #3

Pretty funny. Having taught low-temperature condensed matter labs, a big part of the grade is figuring out what went wrong, and either correcting for it, or at least acknowledging that it went wrong. The student needed to give more information about the experimental setup (what instruments did they use? four point or two point resistance? resistivity vs resistance? what is R_0?) and why they think the experiment didn…

My understanding of undergrad lab work is that the point is not to get results, it's to learn how to do lab work.

Usually on a Friday afternoon/early evening while other non-Science/Engineering types are out having something called a Social Life ...

Re: Electron band structure in germanium, my ass (2000)

#76

Post by baz00 »

jiggawatts wrote: post #7

As an odd coincidence, I did the same experiment on a shoestring budget with substandard equipment also. I too used a fancy computer algorithm to get a best fit. Except that I managed to get four significant decimal places in the result — an improvement over the (also outdated) textbook. The author of the angry rant had a life-defining experience of overwhelming frustration. The same scenario resulted in a positive l…

Talking of a shoestring budget, sometimes it's a good thing. I actually learned more useful things about EE by fixing broken test gear than doing an undergraduate course. The course was so heavily theoretical that when it came to actually building prototypes, nothing worked and no one knew why, not even the lab techs. So I spent most of the time going round helping fixing people's limping final year projects.

Life is what you take out of it :)

Re: Electron band structure in germanium, my ass (2000)

#77

Post by ilyt »

doctorwho42 wrote: post #59
robocat wrote: post #26

Earlier quoted context omitted.

> on old equipment that would break during the experiment Isn’t that closer to the real conditions in a research lab? I met some NASA scientists doing atmospheric sampling on a plane, and they had to accompany their equipment to manage any equipment glitches during the expensive sampling process (a custom modified 747 flying from Hawaii to New Zealand IIRC)

Can confirm, work in a top physics university in the lab. It is not a rare sight to see equipment from 10, 20, 30 years ago still in operation. Though it really depends on the equipment. Optics? They don't really go bad if you treat them right. Electronics? You'd be surprised as the quality of design and fab went into that plastic box that looks older than you. Really physics discovery is partially limited by equipme…

Yeah I've bought some old test equipment and it's a wonder than you just plug it in and it is still within specs. They knew how to build them back when HP was called HP and not agilent/keysight/whatever they rename themselves in next decade.

Re: Electron band structure in germanium, my ass (2000)

#78

Post by wholinator2 »

splittingTimes wrote: post #5

Exactly my experience back in the days doing the mandatory "advanced experimental physics laboratory semester" where you had to do like 14 vastly different experiment of the caliber described in that post in the course of one semester on old equipment that would break during the experiment, with less than motivated PhD students or post grads as teachers. Of the 14 experiments only two worked and we got the expected r…

Wow! I'm less than a year from applying to grad programs and all of my undergrad research experience is in very similar things. Theoretical is my jam. Did you do a PhD? If so do you now believe it was worth it?

Re: Electron band structure in germanium, my ass (2000)

#80

Post by aragilar »

javajosh wrote: post #9
splittingTimes wrote: post #5

Exactly my experience back in the days doing the mandatory "advanced experimental physics laboratory semester" where you had to do like 14 vastly different experiment of the caliber described in that post in the course of one semester on old equipment that would break during the experiment, with less than motivated PhD students or post grads as teachers. Of the 14 experiments only two worked and we got the expected r…

Yeah I don't quite understand how the physics curriculum is set. There is more and more physics discovered over time and yet the time you get to study remains the same. 4 years is not enough time to learn the math and physics you need to do anything real, not counting the other important stuff you need to do (like English comp and partying and getting your heart broken).

Astronomy tends to be a way to get "newer" physics involved (at least in terms of discoveries), but it's also worth noting that formulations used usually evolve from what was originally published (Maxwell's equations are a well-known example), so you're getting more of a cleaned-up version, with insights based on newer discoveries.
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