Historical and general.?The idea of stimulating or ' whipping up ' the physical and mental powers of individuals undergoing especially laborious efforts is not a new one. Even in ancient days it was known that certain substances could give the tired and exhausted individuals added strength. These stimulant substances have been commonly called ' dopes \ The term ' doping' in a wider sense means

Measurements of the resistivity, magnetoresistance, and penetration depth were made on films of La1.85Sr0.15CuO4, with up to 12 at. % of Zn substituted for the Cu. The results show that the quadratic temperature dependence of the inverse square of the penetration depth, indicative of d-wave superconductivity, is not affected by doping. The suppression of superconductivity leads to a metallic no...

The effect of Ag doping on the electronic structure of a stable thiolate-protected Au(25) cluster (Au(25)(SR)(18)) was studied by measuring the optical spectra of Au(25-n)Ag(n)(SC(12)H(25))(18) (n = 0-11) and the results reveal that the electronic structure of Au(25)(SC(12)H(25))(18) is sensitive to Ag doping and is continuously modulated by incorporation of Ag atoms.

How are the properties of a metal changed by strong inelastic scattering? We investigate this question within the two-dimensional t-J model using extended dynamical mean field theory and a generalized noncrossing approximation. Short-ranged antiferromagnetic fluctuations lead to a strongly incoherent single particle dynamics, large entropy, and resistance. Close to the Mott transition at low ho...

We study the Néel temperature of quasi-one-dimensional S = 1/2 antiferromagnets containing nonmagnetic impurities. We first consider the temperature dependence of the staggered susceptibility of finite chains with open boundary conditions, which shows an interesting difference for even and odd length chains. We then use a mean field theory treatment to incorporate the three-dimensional intercha...

Since carrier doping of two-leg spin ladders can theoretically induce a superconductive state, investigation of such systems is of great use in the study of superconductivity. In this paper, we report the successful creation of a non-magnetic impurity doped into a two-leg molecular spin ladder and the characterization of its magnetic properties.

Doping-tunable mid-infrared extraordinary transmission is demonstrated from a periodic metal hole array patterned on n-InSb. The polarization-dependent transmission was measured at room temperature and 77 K. In addition, the extraordinary transmission was measured for incident angles from 0 degrees to 35 degrees in 5 degrees steps. A fundamental resonance shift of approximately 123 cm-1 (1.4 mi...

We study the dynamics of metallic vertical stripes in cuprates within the three-band Hubbard model based on a recently developed time-dependent Gutzwiller approximation. As doping increases, the optical conductivity shows transfer of spectral weight from the charge-transfer band towards (i) an incoherent band centered at 1.3 eV, (ii) a Drude peak, due mainly to motion along the stripe, and (iii...