3 ms·

I don't really have a good understanding for why the high pressures are required. Any ELI 5 explanations?

opwieurposiu 7y ago
The high pressure pre-distorts the lattice making it easier for cooper pairs to form. A cooper pair allows an electron to essiantly be in two places at once, which causes superconductivity: An electron in a metal normally behaves as a free particle. The electron is repelled from other electrons due to their negative charge, but it also attracts the positive ions that make up the rigid lattice of the metal. This attraction distorts the ion lattice, moving the ions slightly toward the electron, increasing the positive charge density of the lattice in the vicinity. This positive charge can attract other electrons. At long distances, this attraction between electrons due to the displaced ions can overcome the electrons' repulsion due to their negative charge, and cause them to pair up. https://en.wikipedia.org/wiki/Cooper_pair https://en.wikipedia.org/wiki/Cooper_pair
klyrs 7y ago
I'm not a physicist, but I work adjacent to people who do neat stuff with superconductors... hopefully they wouldn't be too mad about the broad strokes I'm using here. Superconductivity isn't just a property of a material -- it's a property of an arrangement of atoms. When you put a material under extreme pressures, the atoms are smashed closer together; and the properties of the material can change significantly. For example, diamonds are made by smashing graphite at extreme pressures -- sufficiently high pressure can completely rearrange the crystalline structure. That prepares us for the question; what's superconductivity? The answer is complicated, physicists don't really know the full story; but here's a simplified intuitive picture. We imagine atoms as being positively-charged nuclei with clouds of negatively-charged electrons. When these atoms are packed into a crystalline lattice, and the resulting material is a conductor, then the electrons are fairly free to move about the whole lattice -- they aren't bound to a single atom. When the electrons move about, they attract nearby nuclei -- the atoms in the lattice shift towards them! In a superconductor, something quite amazing happens: when atoms shift towards one electron, it can make room for another electron -- this process causes the electrons to buddy up, and act in a coordinated fashion. These two electrons quickly make other friends, and in short order they're all acting in concert! So, back to high-pressure superconductivity. We've applied a high amount of pressure to a material which isn't normally superconducting. Its atoms have rearranged themselves into a new crystalline lattice, which is quite densely packed. The electrons, too, must be densely packed -- so they have greater opportunities to make friends.

The high pressure pre-distorts the lattice making it easier for cooper pairs to form. A cooper pair allows an electron to essiantly be in two places at once, which causes superconductivity: An electron in a metal normally behaves as a free particle. The electron is repelled from other electrons due to their negative charge, but it also attracts the positive ions that make up the rigid lattice of the metal. This attraction distorts the ion lattice, moving the ions slightly toward the electron, increasing the positive charge density of the lattice in the vicinity. This positive charge can attract other electrons. At long distances, this attraction between electrons due to the displaced ions can overcome the electrons' repulsion due to their negative charge, and cause them to pair up. https://en.wikipedia.org/wiki/Cooper_pair https://en.wikipedia.org/wiki/Cooper_pair

klyrs 7y ago

I'm not a physicist, but I work adjacent to people who do neat stuff with superconductors... hopefully they wouldn't be too mad about the broad strokes I'm using here. Superconductivity isn't just a property of a material -- it's a property of an arrangement of atoms. When you put a material under extreme pressures, the atoms are smashed closer together; and the properties of the material can change significantly. For example, diamonds are made by smashing graphite at extreme pressures -- sufficiently high pressure can completely rearrange the crystalline structure. That prepares us for the question; what's superconductivity? The answer is complicated, physicists don't really know the full story; but here's a simplified intuitive picture. We imagine atoms as being positively-charged nuclei with clouds of negatively-charged electrons. When these atoms are packed into a crystalline lattice, and the resulting material is a conductor, then the electrons are fairly free to move about the whole lattice -- they aren't bound to a single atom. When the electrons move about, they attract nearby nuclei -- the atoms in the lattice shift towards them! In a superconductor, something quite amazing happens: when atoms shift towards one electron, it can make room for another electron -- this process causes the electrons to buddy up, and act in a coordinated fashion. These two electrons quickly make other friends, and in short order they're all acting in concert! So, back to high-pressure superconductivity. We've applied a high amount of pressure to a material which isn't normally superconducting. Its atoms have rearranged themselves into a new crystalline lattice, which is quite densely packed. The electrons, too, must be densely packed -- so they have greater opportunities to make friends.