Why both memory states remain stable

1:03:16and so um like my electrons aren't going through but everything is kind of inert right now let's say I have oxygen vacancy highway in that low resistance state what prevents the oxygen vacancy highway from moving around >> at high temperature right at high temperature if I've got these like vacancy lines where the electrons are going through, but those vacancies can move as >> we talked about earlier. They're not stationary. They're not fixed or >> Yeah. Yeah. Yeah. So, what's preventing those guys from moving around at high temperature when there's all this jiggle? It has to do with something called phase separation. There was a paper about this where the system

1:03:58reaches thermodynamic flux equilibrium where there's a net migration of zero meaning that the material separates into an oxygenrich insulating phase and then an oxygen poor conducting phase. And it's that same argument about oil and water. There's going to be parts of the hneium oxide that have a lot of these oxygen vacancies and then there's going to be parts that don't. And those guys don't want to mix together >> because they become like oil and water. Now, how can we tell in our new memory? Well, they did electron energy loss spectroscopy, which is similar to the X-ray stuff that I was talking about. Like the electrons are now coming out, and then we measure the the energy of

1:04:40the electrons. The main thing that I want you to see is in the low resistance state, which is on the bottom. So, the color tells you how much oxygen vacancy there is. The darker it is, the more oxygen vacancy there is. So that's why the low resistance state at the bottom that has it's kind of darker because there's a lot more oxygen vacancies. The the key thing that I want you to notice is on the bottom we're plotting the number of oxygen vacancies as a function of space. Like we're going we're moving along in nanometer position. We're moving along our meister and we're plotting how much oxygen vacancy there is. If you if you expect a lot of

1:05:20mixing, it should be at equilibrium. But if there's not a lot of mixing, there should be clumps where there's a lot of oxygen vacancy and then not a lot of oxygen vacancy >> because of this oil and wild oil and water you just talked about. >> And that's what we're seeing. We're seeing a very bumpy profile, right? There's certain spots where there's a lot of oxygen vacancy and then other spots that there aren't. If this stuff mixed, it would look like the middle plot >> in that high resistance state. >> Mhm. >> Right. >> Mhm. Yes. >> But because it's not mixing, you get this valley and mountain landscape. And so part of what we're saying is there's two dynamics here. There's both a dynamic between the inter how the tungsten and the graphine relate

1:06:00>> and then the the the halified oxygen. >> Yeah. Um, halfneium halfneium oxide should be halfneium oxide in the middle also has dynamics that not that are com that combine with the relationship between the tungsten and the graphine such that the graphine doesn't want to create the highway and the oxide in the middle also doesn't allow movement. Yeah. And so both of these things combined are are meaningful for the impact in terms of from an industrial or performance perspective. And it's both things not just the ends the the ends of the sandwich. >> Exactly. Yeah. So both the high

1:06:42resistance state which is the one the or sorry no the high resistance is the zero cuz that's like the the electrons aren't moving and then the low resistance state where there is current that's the one. Both of those are now stable. >> Right. Right. >> Uh for for dynamics that we just walked through. >> Mhm. which is which is which is an important point because I was gonna end up asking but what about the middle stuff? >> Yeah. Yeah. The middle stuff is also oil and water. >> Right. Right. Right. >> It's kind of cool. >> Um and they did a lot of benchmarking of like okay what what is all the state-of-the-art and then where is this >> and um it's kind of crazy retention which is how how long it takes and the temperature. That's part A. You want it

1:07:22to be high temperature high retention. So you've got a desired corner >> that's the shaded and there's a [clears throat] star where the current work is and all of the other riff raff >> is not even close >> is not even close. Um you've got the writing endurance in B versus temperature again the only star in the desired corner is this work. >> Um C the onoff ratio versus the temperature desired corner is us. the spiderweb diagram. Um the yellow is the current work and it's always >> larger >> in temperature, in retention, in endurance, in the device size, all sorts of stuff. Now, there is a little bit of

1:08:04uh photoshoppery happening here, [laughter] right? Because I could easily make the desired corner like elsewhere, but but in any case, it's in by every metric, it's always in it's the most in that corner. So whatever desired corner you made, it would always be the most >> out there. Right. >> It's the closest to the optimal regardless of made whether you made the desired outcome smaller or large or whatever. >> Yeah. Yeah. Yeah. But a game recognizes game cuz like I've done that. >> I know what you're Yeah. I'm going to make this square right here so that all the other >> But like mine just mix it [laughter] in. >> Yeah. But in this case, I think it's like fairly obvious and I don't think they're doing any shenanigans. I just

1:08:44thought that was kind of funny as a plot. Um, and finally like to cuz I think they knew that people would call BS right? >> So they took a video of their lab. >> They're like proof. >> They're like this is proof. And the and the thingy shows, oh, 700 degrees Celsius. And they've got their they've got like a computer with their with the two electrodes on the on the two on the the the titanium and the graphine. And they're measuring the onoff ratio and they're measuring the hysteresus curve. And here you can see the hysteresus curve. Like, okay, I turned the voltage up, I turn the voltage down. I'm getting this hysteresus. Guys, this is happening in

1:09:25real time. I'm not making this stuff up. Like I think it's really cool that like this is part of the supplement on the science website because like um whenever you publish right there's the main figures and the main text and then you provide supplementary data and supplementary figures. A lot of the figures that we've seen here um in today's episode are from the supplement >> and this is a supplementary video that they show. Okay guys, here's my hysteresus curve. It's definitely a memeister. This is happening at 700 degrees Celsius and it's definitely working. >> Pix or it didn't happen. >> Yeah. >> Uh in uh front tier science research this but

1:10:05it's also kind of like I I think one people one thing you know as we always talk about is scientists are some of the most skeptical people especially when it's other people that say they did something. >> It's like why didn't I think of that? >> I [laughter] don't I don't believe you. >> Yeah. >> But here Yeah. It's like, okay, here's 704° C, guys. There's my thermometer. [laughter] >> God, this is so good because, you know, and I think you've you've done a good job of how walking us through to kind of understand that there's a fundamental insight that happens that then you you take to the end of possibility or the end of kind of the story in order to get to something that's practical. And it

1:10:48was a very it was maybe subtle um for folks who are material scientists and who work in the space but if you're not in this lane um it can seem like oh this is a subtle point that has such huge implications and >> they've used graphine as the other part of this layer here. Are there other things that have different >> performance characteristics? Yeah, maybe we can now start maybe we can now start um replacing the tungsten. I don't know, >> right? And then and then what does that do? >> Yeah, it just it opens up all sorts of possibilities,