To what degree is Hg-1201 able to act as an archetype of HTSC cuprate phenomena? From Seebeck results to stripe phase behaviour

Abstract

Upon closely examining the Seebeck behaviour of Hg-1201 we have discovered that the system, whether stoichiometric or mercury deficient, appears to behave in similar fashion to the LBCO and YBCO-123 systems in that a dip appears in Tc ( p ) at p ~1/8. We have earlier indicated that this concentration of holes marks the point at which stripe phase formation in the organization of charge and spin in the two-subsystem, mixed-valent, HTSC materials passes from one charge wall loading scheme to another. We observe a strong difference in doping characteristics between the mercury-deficient and mercury-stoichiometric systems, and assemble here a plausible scenario of what is involved. While HgBa2 CuO4+ indeed does offer very considerable potential advantages as an archetype to the cuprate HTSC phenomenon, excess anion systems like this clearly introduce materials complexities. These will always demand careful attention and perhaps not endear the system to many accustomed to the relative simplicities of a cation-doped system.

Bosonic mode interpretation of novel scanning tunnelling microscopy and related experimental results, within boson–fermion modelling of cuprate high-temperature superconductivity

“…It would be most valuable to have this work repeated now with high quality Hg-1201, a system where the hole doping is procured via interstitial oxygen rather than cationic substitution. The mercury materials, as with all others examined, certainly provide evidence of a 1 / 8 anomaly(Farbod et al 2000, Wilson & Farbod 2000. Within the fluctuational mêlée the effective doping level in the LSCO case has proven to be such that it is able to stand locally far removed from the mean value (Singer 2003ab), to such a degree that magnetic moments in fact can emerge at select sites even within mildly underdoped material.…”

“…However the type of disorder being addressed in [51] is restricted to that associated solely with static doping disorder and frozen charge segregation, as the recent STM results could at first sight appear to flag [52]. anomaly [54]. Within the fluctuational mêlée the local effective doping level has proved in the LSCO case to be such that it can stand far different from the mean value [53], to such a degree that magnetic moments can in fact emerge at select sites within even mildly underdoped material.…”

“…In view of the above it is rather strange Loram, Tallon and Liang in a recent preprint [51] have chosen to play down the fragmented circumstances prevailing in the cuprate systems, especially when underdoped. anomaly [54]. Within the fluctuational mêlée the local effective doping level has proved in the LSCO case to be such that it can stand far different from the mean value [53], to such a degree that magnetic moments can in fact emerge at select sites within even mildly underdoped material.…”

EVIDENCE FOR STRIPE PHASE FORMATION IN HgBa2CuO4+δ SUPERCONDUCTOR

“…It is to be noticed that this method of preparation, which is the most commonly used method, leads to mercury deficient samples. We have discussed in length [7] that the Hg deficient samples can have quite different properties from stoichiometric ones. The hole concentration (p) was measured using room temperature TEP based on the empirical "universal rule" [8].…”

A Tale of Two Entangled Instabilities—The Dual Role of δ-O in HgBa2Can-1CunO2(n+1)+δ

“…Holes doping of the CuO 2 planes in the HgBa 2 CuO 4+δ superconductors, a representative of the cuprate class of superconductors discoverer three decades ago [1], is accomplished by intercalation of electrons accepting oxygen into the so-called charge reservoir [2]. While affecting the structure of these buffer layers the sole role of the added oxygen relevant to high-critical temperature superconductivity (HTS) is commonly assumed to comprise control the charge carrier concentration in the Zhang-Rice band (ZRB) [3], lower Hubbard bands (LHB), and upper Hubbard bands (UHB) manifold residing in the CuO 2 plane.…”