Hi, I am a student who's learning about quantum mechanics. I was reading about the RTD (Resonant tunneling diode) and I got the general idea. However, I was looking at a I vs V graph and came up with a question. Since Resistance = V/I, the inverse slope of the I vs V graph has to be the resistance. (for a simple model of RTD, it had a giant peak). Now, the problem is, for the rising part of the peak, I understand, but what is the physical interpretation of the falling part of the peak? (the negative resistance) Does that simply mean the flow of the electron is greater? Thanks!