Charge Order and Suppression of Superconductivity in HgBa2CuO4+d at High Pressures

Abstract

New insight into the superconducting properties of HgBa2CuO4 (Hg-1201) cuprates is provided by combined measurements of electrical resistivity and single crystal X-ray diffraction under pressure. The changes induced by increasing pressure up to 20 GPa in optimally doped single crystals were investigated. The resistivity measurements as a function of temperature show a metallic behavior up to ~10 GPa that gradually passes into an insulating state, typical of charge ordering, which totally suppresses superconductivity above 13 GPa. The changes in resistivity are accompanied by the apparition of sharp Bragg peaks in the X-ray diffraction patterns, indicating that the charge ordering is accompanied by a 3D oxygen ordering. Considering that pressure induces a charge transfer of about 0.02 at 10 GPa, our results are the first observation of charge order competing with superconductivity developed in the overdoped region of the phase diagram of a Hg-based cuprate.

Functional Nanoscale Phase Separation and Intertwined Order in Quantum Complex Materials

“…Diffuse CDW satellites have been detected at qCDW = 0.23a* + 0.16c* and qCDW = 0.23b* + 0.16c* (where a*, b*, and c* are the lattice units in the reciprocal space) around the (108) Bragg peak, below the onset temperature TCDW = 240 K [7]. Resolution-limited streaks connecting the Bragg peaks, due to atomic O-i stripes in the HgOy spacer layers, have been measured in agreement with previous experiments [6,32].…”

“…NPS shows that intertwined and interlocked nanoscale lattice structures form heterostructures at the atomic limit [13]. This induces the emergence of novel functionalities, such as high-temperature superconductivity, in complex quantum materials as organics [13][14][15][16][17][18][19][20], doped perovskites [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39], iron-based superconductors [40][41][42][43][44], chargedensity-wave materials [45][46][47][48][49][50][51][52], manganites showing colossal magnetoresistance [53][54][55][56][57], doped diborides [58][59]…”

Scale-Free Distribution of Oxygen Interstitial Wires in Optimum-Doped HgBa2CuO4+y

“…The results provide compelling experimental evidence for the location of the oxygen interstitial (O-i) content, y, which occupies the interstitial site ½, ½, and 0 in the basal plane of HgBa2CuO4+y. The arrangement of O-i gives rise to intriguing diffraction features constituted by clear diffuse streaks crossing the Bragg peaks along all the three crystallographic directions [56][57][58]. In Figure 1b, we show a typical diffuse streak between the (3,3) and (3,4) reflections in the hk diffraction plane.…”

“…The texture of oxygen interstitials (O-i) related with their selforganization due to their large mobility in the space layers above about 200 K was detected by advanced scanning micro-X-ray diffraction, in layered perovskites, such as nickelates La2NiO4+y [33,34] and in several families of cuprate high-temperature superconductors (HTS), such as doped La2CuO4+y (La214) [35][36][37][38][39][40][41][42], YBa2Cu3O6+y (Y123) [43][44][45], and Bi2Sr2CaCu2O8+y (Bi2212) [46][47][48][49]. In this work, we focus on HgBa2CuO4+y (Hg1201) at optimum doping [50][51][52][53][54][55][56][57][58][59][60], which is the simplest member of the mercury-based cuprate compounds that provides the highest superconducting transition temperature. HgBa2CuO4+y has a simple tetragonal average structure with average Cu-O bond length of 194 pm [54], showing self-organization of a nematic phase with co-existing O-i atomic stripes [56,57] running in the a-direction (100) and bdirection (010) of the ab plane.…”