I was going through an example of conductors and insulators in terms of energy gap and that got me thinking. For conduction, free electrons need to be able jump from the Valence band to conduction band. Let's suppose the temperature of the material is 0°K, which is absolute 0. At absolute cold, even the atoms, and subatomic particles will cease motion. If the temperature is 0°K, then even in conductors, which have no forbidden gap between the conduction and valence band, there would be no motion of particles and hence, even the conductor would be an insulator. Am I right? If no, then please elaborate how. Thanks in advance.
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$\begingroup$ All motion does not cease at absolute zero. That is a classical physics description. $\endgroup$– BowlOfRedCommented Dec 5, 2022 at 16:32
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1$\begingroup$ Most materials will superconduct instead at close to 0K $\endgroup$– JamesCommented Dec 5, 2022 at 16:39
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$\begingroup$ Can I please have more explanation on both of your comments. Specially @James $\endgroup$– AsadCommented Dec 5, 2022 at 16:40
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1$\begingroup$ @Asad it's been done in experiments. "Hundreds of materials are known to become superconducting at low temperatures. Twenty-seven of the chemical elements, all of them metals, are superconductors in their usual crystallographic forms at low temperatures and low (atmospheric) pressure. Among these are commonly known metals such as aluminum, tin, lead, and mercury and less common ones such as rhenium, lanthanum, and protactinium. In addition, 11 chemical elements that are metals, semimetals, or semiconductors are superconductors at low temperatures and high pressures. $\endgroup$– JamesCommented Dec 5, 2022 at 16:44
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$\begingroup$ ...Among these are uranium, cerium, silicon, and selenium. Bismuth and five other elements, though not superconducting in their usual crystallographic form, can be made superconducting by preparing them in a highly disordered form, which is stable at extremely low temperatures. Superconductivity is not exhibited by any of the magnetic elements chromium, manganese, iron, cobalt, or nickel." en.wikipedia.org/wiki/…. $\endgroup$– JamesCommented Dec 5, 2022 at 16:44
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In metals, electrons need not jump. They are always present in the conduction band. Even for metals that aren't superconductors, resistivity decreases with decreasing temperature, as scattering of electrons by thermal phonons declines.
