Quantum phase transition from superconducting to insulating-like state in a pressurized cuprate superconductor

Abstract

Copper oxide superconductors continue to fascinate the communities of condensed matter physics and material sciences because they host the highest ambient-pressure superconducting transition temperature and unconventional electronic behaviour that are not fully explained1–3. Searching for universal links between the superconducting state and its normal metallic state is believed to be an effective approach to elucidate the underlying mechanism of superconductivity. One of the common expectations for copper oxide superconductors is that a metallic phase will appear after the superconductivity is entirely suppressed by chemical doping4–8 or the application of a magnetic field9. Here we report the first observation of a quantum phase transition from a superconducting state to an insulating-like state as a function of pressure in Bi2Sr2CaCu2O8+δ (Bi2212) superconductors with two CuO2 planes in a unit cell for doping below, at and above a level that achieves the highest transition temperature. We also find the same phenomenon in related compounds with a single CuO2 plane as well as three CuO2 planes in a unit cell. This apparently universal phenomenon poses a challenge for achieving a unified understanding of the mechanism of high-temperature superconductivity.

An ultrafast spectroscopy system for studying dynamic properties of superconductors under high pressure and low temperature conditions

“…2(b), which shows that the resistance of Bi-2212 film decreases with temperature and superconducting transition occurs at 86.8 K, which is consistent with most results of T c of Bi-2212. [39,40] The above characterization experiments confirm that Bi-2212 thin films have good quality and they are exact superconductors at low temperatures.…”

“…[41] According to the previous report, the structure of the Bi-2212 film is still kept invariable before the pressure increases to 37.0 GPa. [40] In this situation, the variance of pressure can influence the relaxation process of photo-generated species in Bi-2212 film, but can not affect the corresponding relaxation mechanism. If the pressure goes higher and the phase transition of Bi-2212 film occurs, in which the photogenerated species in the new phase structure may be different 067801-3 from that of the initial structure, inducing the TA curves may apparently change.…”

“…In other words, increasing environmental pressure may also increase the transition temperature of Bi-2212 film and this tendency is consistent with many theoretical predictions and experimental results. [22,40,42] Actually, the increase in pressure may broaden the electronic cloud distribution of transient species, which may promote the interaction among transient species and accelerate their annihilation through collision recombination. [42] Therefore, the collision recombination at high pressure may be responsible for this rapid component.…”

Modulations in Superconductors: Probes of Underlying Physics

“…iii) The high‐pressure modulation also leads to various exotic phenomena which have not been well understood, e.g., unconventional critical behavior of pressure‐induced Mott transition in organic superconductors, [ 248–250 ] the double‐dome (or so‐called reentrant) superconductivity in IBSC, [ 251,252 ] and more recently the first pressure‐induced SIT in Bi 2 Sr 2 CaCu 2 O 8+ δ . [ 253 ]…”

“…The point of this kind of isovalent substitution is related to the so-called chemical pressure, [247] which has been mentioned at the end of Section 2.1. iii) The high-pressure modulation also leads to various exotic phenomena which have not been well understood, e.g., unconventional critical behavior of pressureinduced Mott transition in organic superconductors, [248][249][250] the double-dome (or so-called reentrant) superconductivity in IBSC, [251,252] and more recently the first pressure-induced SIT in Bi 2 Sr 2 CaCu 2 O 8+δ . [253] What is tuned by pressure in superconductors? The first parameter is carrier density, due to the compressed volume.…”