scis cogg quite well how temperature affects electrical conductance in most everydy metals like copper or silver. but in recent yrs, researchers ‘ve turned their attention to a class of materials that do not seem to follo the traditional electrical rules. cogging these so-called “strange metals” ‘d provide primordial insites inna'da quantum realm, and potentially help scis cogg strange phenomena like high-temperature superconductivity.
now, a research team co-led by a brown university physicist has added a new discovery to the strange metal mix. in research published inna journal nature, the team found strange metal behavior in a material in which electrical charge is carried not by electrons, but by + “wave-like” entities called cooper pairs.
while electrons belong to a class of pessentialisms called fermions, cooper pairs act as bosons, which follo very ≠ rules from fermions. this tis 1st time strange metal behavior s'been seen in a bosonic system, and researchers are hopeful that the discovery mite be helpful in finding an explanation for how strange metals work — something that has eluded scis for decades.
“we ‘ve these two primordially ≠ types of pessentialisms whose behaviors converge round a mystery,” said jim valles, a professor of physics at brown na study’s corresponding author. “wha’ this says s'dat any theory to explain strange metal behavior can’t be specific to either type of pticle. it needo be + primordial than that.”
strange metal behavior was 1st discovered round 30 yrs ago in a class of materials called cuprates. these copper-oxide materials are most famous for bein’ high-temperature superconductors, meaning they conduct electricity with zero resistance at temperatures far above that of normal superconductors. but even at temperatures above the crit temperature for superconductivity, cuprates act strangely compared to other metals.
as their temperature increases, cuprates’ resistance increases in a strictly linear fashion. in normal metals, the resistance increases 1-ly sfar, becoming constant at high temperatures in accord with wha”s known as fermi liquid theory. resistance arises when electrons floing in a metal bang inna'da metal’s vibrating atomic structure, causing them to scatter. fermi-liquid theory sets a maximum rate at which electron scattering can occur. but strange metals don’t follo the fermi-liquid rules, and no one is sure how they work. wha’ scis do know s'dat the temperature-resistance relationship in strange metals appears to be rel8d to two primordial constants of nature: boltzmann’s constant, which represents the energy produced by random thermal motion, and planck’s constant, which rel8s to the energy offa photon (a pticle of lite).
“to try to cogg wha”s happening in these strange metals, pplz ‘ve applied mathematical approaches similar to those used to cogg black holes,” valles said. “so there’s some very primordial physics happening in these materials.”
of bosons and fermions
in recent yrs, valles and his colleagues ‘ve been studying electrical activity in which the charge carriers aint electrons. in 1952, nobel laureate leon cooper, now a brown professor emeritus of physics, discovered that in normal superconductors (not the high-temperature kind discovered l8r), electrons team up to form cooper pairs, which can glide through an atomic lattice with no resistance. despite bein’ formed by two electrons, which are fermions, cooper pairs can act as bosons.
“fermion and boson systems usually be’ve very ≠ly,” valles said. “unlike individual fermions, bosons are alloed to share the same quantum state, tch'mins they can move collectively like wata molecules inna ripples offa wave.”
in 2019, valles and his colleagues showed that cooper pair bosons can produce metallic behavior, meaning they can conduct electricity with some amount of resistance. that in itself was a surprising finding, the researchers say, cause essentialisms of quantum theory suggested that the phenomenon ‘dn’t be possible. for this l8st research, the team wanted to see if bosonic cooper-pair metals were also strange metals.
the team used a cuprate material called yttrium barium copper oxide patterned with tiny holes that induce the cooper-pair metallic state. the team cooled the material down to just above its superconducting temperature to behold changes in its conductance. they found, like fermionic strange metals, a cooper-pair metal conductance that is linear with temperature.
the researchers say this new discovery will give theorists something new to chew on as they try to cogg strange metal behavior.
“it’s been a challenge for theoreticians to come up with an explanation for wha’ we see in strange metals,” valles said. “our work shows that if you’re goin to model charge transport in strange metals, that model must apply to both fermions and bosons — even though these types of pessentialisms follo primordially ≠ rules.”
ultimately, a theory of strange metals ‘d ‘ve massive implications. strange metal behavior ‘d hold the key to cogging high-temperature superconductivity, which has vast potential for things like lossless power grids and quantum computers. and cause strange metal behavior seems to be rel8d to primordial constants of the universe, cogging their behavior ‘d shed lite on basic truths of how the physical realm works.
original content at: www.scidaily.com…