The two triangles appear for every charge transition, not only (1,1). They are the "triple points" but at high bias. Inside the triangles there could be other lines, and some of them correspond to excited states, such as triplet for (1,1) - would be a line parallel to the base of the (1,1)->(0,2) triangles, but this line will be near the triangle tip. The reason why there are two triangles is because there is an "electron transfer cycle" and a "hole transfer cycle" through the double dot.
Love the lectures! Thanks for putting these online. No idea whether you'll see this, but appreciate the source of education nonetheless. A question though about the graph at 41:28, showing the excited state diamonds. Why can current flow at Vsd=0 for the GS(N)GS(N+1) transition, and not for the ES(N)GS(N+1) or GS(N)ES(N+1)? In my head, each of these acts as an accessible transitionon the dot, and I would have though that if the chemical potential lines for any of these on the "ladder" fall within the Vsd window, then current could flow? Is the reason because the Excited States will just quickly decay to the Ground States, so cannot be used to support current unless the Ground States are also occupied to support current flow? Cheers Sergey!
Great lecture! Thanks for uploading these. A question, why are there always two triangles in DQDs? How to get the second triangle in each pair? Are they corresponding to singlet states or just the first excited orbital states? Thanks.
The two triangles appear for every charge transition, not only (1,1). They are the "triple points" but at high bias. Inside the triangles there could be other lines, and some of them correspond to excited states, such as triplet for (1,1) - would be a line parallel to the base of the (1,1)->(0,2) triangles, but this line will be near the triangle tip. The reason why there are two triangles is because there is an "electron transfer cycle" and a "hole transfer cycle" through the double dot.
Love the lectures! Thanks for putting these online.
No idea whether you'll see this, but appreciate the source of education nonetheless.
A question though about the graph at 41:28, showing the excited state diamonds. Why can current flow at Vsd=0 for the GS(N)GS(N+1) transition, and not for the ES(N)GS(N+1) or GS(N)ES(N+1)? In my head, each of these acts as an accessible transitionon the dot, and I would have though that if the chemical potential lines for any of these on the "ladder" fall within the Vsd window, then current could flow?
Is the reason because the Excited States will just quickly decay to the Ground States, so cannot be used to support current unless the Ground States are also occupied to support current flow?
Cheers Sergey!
Great lecture! Thanks for uploading these.
A question, why are there always two triangles in DQDs? How to get the second triangle in each pair? Are they corresponding to singlet states or just the first excited orbital states?
Thanks.
why spin orbit coupling two couples the energy levels of electrons with opposite spin in the two dots
Thanks Professor,
So the second triangle is with respect to (1,1) singlet states. am I right?
You can see the explanation for double triangles here: arxiv.org/abs/cond-mat/0205350, see figures 5 and 8.
QUANTUM ENERGY?
Thank you for explaining !