Introduction and motivation

In an effort to get more content on Tildes, I want to try and give an introduction on several 'hot topics' in semiconductor physics at a level understandable to laypeople (high school level physics background). Making physics accessible to laypeople is a much discussed topic at universities. It can be very hard to translate the professional terms into a language understandable by people outside the field. So I will take this opportunity to challenge myself to (hopefully) create an understandable introduction to interesting topics in modern physics. To this end, I will take liberties in explaining things, and not always go for full scientific accuracy, while hopefully still getting the core concepts across. If a more in-depth explanation is wanted, please ask in the comments and I will do my best to answer.

Today's topic

I will start this series with an introduction to spintronics and spin transistors.

What is spintronics?

Spintronics is named in analogy to electronics. In electronics, the flow of current (consisting of electrons) is studied. Each electron has an electric charge, and by pulling at this charge we can move electrons through wires, transistors, creating modern electronics. Spintronics also studies the flow of electrons, but it uses another property of the electrons, spin, to create new kinds of transistors.

What are transistors?

Transistors are small electronic devices that act as an on-off switch for current. We can flip this on-off switch by sending a signal to the transistor, so that the current will flow. Transistors are the basis for all computers and as such are used very widely in modern life.

What is spin?

Spin arises from quantum mechanics. However, for the purpose of explaining spin transistors we can think of an electron's spin as a bar magnet. Each electron can be thought of as a bar magnet that will align itself to a nearby magnetic field. Think of it as a compass (the electron) aligning itself to a fridge magnet when it's held near the compass.

What are spin transistors and how do they work?

Spin transistors are a type of transistor whose on-off switch is created by magnets. We take two bar magnets, whose north poles are pointed in the same way, and put them next to each other, leaving a small gap between them. This gap is filled with a material through which the electrons can move. Now we connect wires to the big bar magnets and let current (electrons!) flow through both magnets, via the gap. When the electrons go through the first magnet, their internal magnets will align themselves to the big bar magnet. However, once they are in the gap the electrons' internal magnets will start rotating and no longer point in the same direction as the big bar magnets. So that when the electrons arrive at the second magnet, they will be repelled just like when you try to push the north poles of two magnets together. This means the current will not flow, and the device is off! So, how do we get it to turn on?

By exposing the gap to an electric field, we can control the amount of rotation the electrons experience (this is called the Rashba effect). If we change the strength of this electric field so that the electrons will make exactly one full rotation while crossing the gap, then by the time they reach the second big bar magnet they will once again be pointing in the right direction. Now the electrons are able to move through the second big bar magnet, and out its other end. So by turning this electric field on, the spin transistor will let current flow, and if we turn the electric field off, no current will flow. We have created an on-off switch using magnets and spin!

That's cool, but why go through the effort of doing this when we have perfectly fine electronics already?

The process of switching between the on and off states of these spin transistors is a lot more energy efficient than with regular transistors. These types of transistors leak a lot less too. Normal transistors will leak, meaning that a small amount of current will go through even when the transistor is off. With spin transistors, this leak is a lot smaller. This once again improves the energy efficiency of these devices. So in short, spin transistors will make your computer more energy efficient. This type of transistor can also be made smaller than normal transistors, which leads to more powerful computers.

Feedback and interest

As I mentioned, I wrote this post as a challenge to myself to explain modern physics to laypeople. Please let me know where I succeeded and where I failed. Also let me know if you like this type of content and if I should continue posting other similar topics in the same format.

Would there be a way to show the number of new posts on a topic since the last time you read it? I find a lot of threads tend to linger for a couple days, and I forget how many comments there were the last time I checked. It would be awesome if it could display something like '10 Comments (2 new)' on a topic I'd visited before.

It would also be awesome if there was a way to highlight the new comments on the page when you click through as well to make it easier to find them.

P.S.: Sorry if this has been covered somewhere else. Still not sure what the best way to find old topics without manually reading every post is.

Frozen chicken wings, about $5 a pound at the local Winco. Defrosted half in the microwave for about 5 minutes. Rubbed on Olive oil, threw in the air fryer for about 30 minutes at 400 degrees (f). Sprinkled on Tumeric, Paprika, garlic powder, onion powder, salt, pepper.

Holy shit is this good.

I noticed that Tildes docs make a point out of using words instead of labels. The stated reason is that icons may be difficult to understand, and I honestly don't get how is this the case.

Icons, when used right, are much more usable and intuitive than any text labels. They are small, distinct, they draw attention and you can tell what they do just by looking at them instead of reading them.

Take the classic upvote/downvote scrollers used on Reddit, Imgur, etc. It uses icons for upvotes and downvotes, but there isn't a single person I know who doesn't know what those mean. It's intuitive and usable. It doesn't require localization. It just works.

In contrast, the "Vote (10)" button on Tildes. It uses text, on a page full of text. It's an important UI element, one of the most used UI elements really, but it's not visually highlighted in any way. The amount of votes, which is an important metric, isn't distinct, making it hard to read. The "text button" style it uses is usually reserved for buttons that are used rarely, such as "Edit" or "Delete", or buttons that open more menus, such as "Edit" or "Reply". It's not intuitive.

Yes, this is a minor thing, but it's minor things that make the overall experience pleasant or unpleasant. And it shows how icons (and highlights), when used right, make user experience better.

I would have to say Pink Floyd's Shine On You Crazy Diamond. It's got a spacey presence in the beginning and the solos hit, which are so wonderfully crafted. The vocals come in and the chorus sounds magnificent and epic in nature. What are your thoughts?

fuck anybody who says my shit isn't cultured.

sorry if my language isn't okay on the site.

v drunk at the moment

here it goes anyway

enjoy.

or don't i guess,

either way.

j'en veux plus
exister
içi.

c'est impossible
à dormir
depuis

février quand
t'étais
parti

la bouteille
à remplacé
therapie

Tu m'as
donné pas de
sympathie

c'est parce'que
toi que je
ecris

tous les chansons
qui parle'd
mourir

ouais c'est
vrai q'je rêve
d'suicide

Je plonge
dans l'alcool
comme piscine

Daily still
wonder if
you miss me

Daddy still
gonna miss
his baby

I really miss
the way you'd
reassure me

comme

"Oauis, papa
c'est que tout va-t-
allez bien

Non, monsieur,
tu ne mourras pas
cette semaine.

Je vais, faire
sûr que je prends
soin de toi

I will love you,
cross my heart and
swear to God. "

"Oauis, papa
c'est que tout va-t-
allez bien

Non, monsieur,
tu ne mourras pas
cette semaine.

Je vais, faire
sûr que je prends
soin de toi

I will love you,
cross my heart and
swear to God. "

J'en veux plus
exister
sans toi

Je m'ai demandé
chaque nuit
pourquoi?

Tu m'as laiseé
completement
pantois

Je'm sens
maintenant
trop inadéquat

Would you like me
better if I had
some photoshop

Would you come to
visit if my breathing
ever stopped

Better yet, I
wonder if I'd rather
have you not

I just wish I had
some truth before
I fade to black

ouais, monsieur.

tu ne mourras pas
cette semaine

write something cool this week?

want to freestyle into the comments and see what you make?

this is your place to share something you wrote that youre proud of.

doesnt have to be a specific style or length, its just gotta be yours.

I know that users can manually set this option as default, but it can be confusing for newcomers to only see, say, 4 threads in the whole group when there are many more than that. This makes it easier to navigate content (especially with a smaller community with less being submitted), is two less clicks for someone who wants to see older submissions, and is easier for new users who may have not found the ‘time sorting’ setting.

So far, I haven’t seen too much moderation aside from bans, etc. dealt out by the admins (unless I’m wrong here and a moderation system is currently in place, please correct me if I’m wrong), but how will this work once Tildes is fully released to the public? Will people who show interest in a certain community be reached out to and asked?

I was posting a something earlier and tried to use an apostrophe in a tag, and it told me off for doing so. Well, kind of, it didn't mention what was wrong, but it was pretty easy to deduce. Can the "tags: Invalid tags" maybe point/link somewhere about what is or isn't allowed?

(also I'm just really curious, what are the limits? I just found out accents [or at least 'tést'] aren't allowed either)

Did you consider putting the name on the bottom of the comment? As tildes invites for high quality discussions witch tend to incent longer comments than elswhere i think it might be better suited to have the name on the end of the comment.

This has some advantages:

• It's easier to notice the autor of a good long text
• When starting to read a comment you don't now the autor yet, so its easier to rate the content instead of the person
• It looks a lot more like a letter, which suits tildes well I think

Maybe it's just me coming from reddit where you close to never meet the same autor twice, so reading the names of the autors does not really matter, and as tildes uses a very similar design I just never seem to notice the name and always have to scroll back up afterwards.