arXiv subjects

Jürgen Röhler

Publications and source records attributed to Jürgen Röhler.

3 recordsLinked to original sources

arXiv2019

x_opt and x_c in Cuprate Superconductors

The characteristic hole concentrations x_opt = 0.16 and x_c = 0.19 in the under- to overdoped transition regime of cuprate superconductors are shown to be intimately interrelated by mesoscale organization of bond-like RVB arrays extending over 3 x 4 copper sites and comprising 2 holes spaced by 3a_0. Columnar organization maximizes T_c but reduces the superfluid stiffness, while zigzag (tweedy) organization maximizes the superfluid stiffness at reduced T_c. The latter goes hand in hand with the closure of the pseudogap. Columnar and zigzag mesoscale organizations of the bond-like RVB arrays are displacively transformed in each other between x_opt and x_c by weak overdoping.

cond-mat.supr-con↗

arXiv2010

Nonlinear Doping of Cuprate Superconductors -- The case of Bi_2Sr_{2-x}La_xCuO_{6+δ}

We analyze the hole doping mechanism in Bi_2Sr_{2-x}La_xCuO_{6+δ} (BSLCO). The singular optimum around x=0.35 is found to be connected with a feedback between the doped CuO_2 layers and its dopant reactant [La^{3+}/Bi^{3+}-O_δ] locking the number of doped holes preferentially on to the universal optimum n_opt=0.16.

cond-mat.supr-con↗

arXiv2006

The bulge in the basal plane area of cuprate superconductors - evidence for 3a singlet hole pairs

The bulge in the doping dependence of the basal plane area in hole doped cuprate superconductors is connected with a non-double-occupancy constraint for the oxygen cages in the CuO_2 lattice. This constraint favors the formation of 3a hole pairs growing to filaments with gapless excitations along the (pi, pi) direction. Thus in the pseudogap regime a nodal metal of hole pairs is created. Densest packed 3a hole pairs stabilize the optimum doped state at n =1/6 ~ 0.16.

cond-mat.supr-con↗