08-Aug-2018 - American Association for the Advancement of Science

Scale-invariant resistivity in cuprates

A new intriguing property of cuprate superconductors has been identified, says a new study, which shows that in very high magnetic fields, the resistivity of a thin-film lanthanum-based cuprate scales linearly with the field. The findings present a challenge for the theories concerning the normal state of the cuprates. Cuprate superconductors display many unusual and unique properties. In their "strange metal" phase, cuprates display resistivity that scales linearly with temperature, which is an anomalous behavior.

One way to study the properties of cuprates in their normal ground state is to apply strong magnetic fields, which suppress superconductivity. However, according to Paula Giraldo-Gallo and colleagues, the direct effects of strong magnetic fields on the cuprates is poorly understood. Giraldo-Gallo et al. studied the electrical transport of a Lanthanum-based cuprate - La2-xSrxCuO4 - within strong magnetic fields and find that resistivity scales linearly with magnetic fields up to 80 tesla.

According to the authors, the linear-in-field resistivity mirrors the linear-in-temperature resistivity of the strange metal phase in more ways than one. Furthermore, the scale-invariant responses are distinct from the quadratic dependence well-known in of ordinary metals, indicating that each is governed by a non-quasipartical mechanism.

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