Jahn–Teller Effect: Scientists Discover New State of Matter Derived From Nonlinear Process, Reports Say The study, led by professor Kosmas Prassides of Tohoku University, claims to have found the matter inside crystal. The Jahn-Teller effect describes geometrical distortion of molecules and ions. anyone up on this?
Here's the Wiki page ... The Jahn–Teller effect, sometimes also known as Jahn–Teller distortion, describes the geometrical distortion of molecules and ions that is associated with certain electron configurations. This electronic effect is named afterHermann Arthur Jahn and Edward Teller, who proved, using group theory, that orbital nonlinear spatially degenerate molecules cannot be stable. http://en.wikipedia.org/wiki/Jahn–Teller_effect It's interesting that they use group theory to prove things about the real world. Fascinating how that developed ... the centuries-old search to solve polynomial equations ended up in the discovery of an abstract mathematical theory, which then turns out to be exactly what was needed to make sense of modern physics. Galois died in 1832; and group theory was first used in quantum mechanics in the late 1920's ... about a hundred years later. You never know when a useless math abstraction will become essential to the world. http://en.wikipedia.org/wiki/Évariste_Galois http://www.math.columbia.edu/~woit/wordpress/?p=191 Please excuse my little digression ... I know a little math but not much about molecules.
Yes indeed. This is chemistry rather than physics, but certainly Group Theory (of symmetry point groups, mainly - though I think space groups are used for giant structures) is used a very great deal in theoretical chemistry. The power of this approach is that it is qualitative rather than numerical. This is important when one realises how intractably complicated numerical solution of wave equations are for polyatomic molecules. The fact that state functions have wavelike properties (superposition, constructive and destructive interference and so on) allows one to rely on symmetry considerations to work out what configurations will lead to lower energy and which to higher energy, without crunching all the numbers, for each electron, in each molecular orbital. I had to learn group theory at university in my quantum chemistry supplementary subject and I must say it was rather brilliant - though I can't remember much of it now. I do just about remember the Jahn-Teller Theorem however, about the distortion of molecules to resolve degeneracy. People used to talk fairly casually about "Jahn-Teller dstortions" of complexes in inorganic chemistry.
This is based on the principle that the team is more than the sum of its parts. A team will place restrictions on all the players, which the players might not place on themselves. These restrictions allow the team to become more than the sum of its parts. A molecule may form a degenerate state; don't hog the ball. This is not normal for that player/molecule, so he feels tension. However, by doing so, the team; crystal, lowers its overall energy; gets even better. The concept of morality uses the same basic principle in that it restricts the behavior of individual molecules/people. This can cause a repressed state of internal pressure due to not being able to act with impulse. In doing so, group life is made much easier in terms of external threats; lower the teams global energy. For example, if nobody can steal, this will place harsh restrictions on thieves. They will have an internal potentiated state that is frustrating to them. But culture, as whole, would be safer, with people able to leave their keys in the car and not need security systems. The team is at lower energy even with degenerate states. If Jahn-Teller distortions were relative to the needs of the individual complexes, they won't want to form degenerate states. The team or crystal would exist at a much higher energy level; more global stress and strain.
Back to the OP, I have just realised that while we talked about the Jahn-Teller theorem, we never dealt with the actual subject of the OP, which seems to be the discovery of superconductivity in Buckminsterfullernes doped with Rubidium: http://motherboard.vice.com/en_au/read/meet-the-newest-state-of-matter-2 I'm not sure quite what these so-called "Jahn-Teller metals" really are. I can only surmise that the degeneracy that Jahn-Teller distortion resolves is somehow reinstated and that the degenerate states can overlap to create a conduction band or something. But there's clearly more to it, since superconductivity is at issue, which requires electrons to pair up to form effective bosons. The pairing mechanism in this case seems not to be understood. So I have more questions than answers at this stage.
Conductivity and other properties are often a function of pressure. As a way of an example, when water freezes, the hydrogen bonds expand; ice expands when it freezes. If we add pressure to water and try to freeze it, the pressure has the impact of keeping the hydrogen bonds from expanding. The result is water will remain a liquid at temperature below the freezing point. In the case of these exotic Jahn-Teller metals, the pressure is physically lowering the distance between atoms, such that electrons states that previously could not integrate, begin to integrate in new ways. Pressure is interesting, because pressure integrates all the forces of nature, with all the forces of nature, and entropy, able to generate pressure. Energy can also generate pressure. For example, gravitational pressure in the core of the earth causes iron to become solid at 6000C, while inducing it into a high temperature magnetic state. The iron would be a gas, on the surface at that temperature, with insulation type properties. Instead gravitational pressure tweaks the EM force and therefore the behavior of the electron orbitals.
