There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Spintronics, or spin electronics, involves the study of active control and manipulation of spin degrees of freedom in solid-state systems. This article reviews the current status of this subject, including both recent advances and well-established results. The primary focus is on the basic physical principles underlying the generation of carrier spin polarization, spin dynamics, and spin-polarized transport in semiconductors and metals. Spin transport differs from charge transport in that spin is a nonconserved quantity in solids due to spin-orbit and hyperfine coupling. The authors discuss in detail spin decoherence mechanisms in metals and semiconductors. Various theories of spin injection and spin-polarized transport are applied to hybrid structures relevant to spin-based devices and fundamental studies of materials properties. Experimental work is reviewed with the emphasis on projected applications, in which external electric and magnetic fields and illumination by light will be used to control spin and charge dynamics to create new functionalities not feasible or ineffective with conventional electronics.

/pdf/spintronics-fundamentals-and-applications-2dx38n6phu.pdf

Spintronics: Fundamentals and applications

There is a special reason for reviewing this book at this time: it is the 50th edition of a compendium that is known and used frequently in most chemical and physical laboratories in many parts of the world. Surely, a publication that has been published for 56 years, withstanding the vagaries of science in this century, must have had something to offer. There is another reason: while the book is a standard fixture in most chemical and physical laboratories, including those in medical centers, it is not as frequently seen in the laboratories of physician's offices (those either in solo or group practice). I believe that the Handbook can be useful in those laboratories. One of the reasons, among others, is that the various basic items of information it offers may be helpful in new tests, either physical or chemical, which are continuously being published. The basic information may relate

Handbook of Chemistry and Physics

The density-matrix renormalization group (DMRG) is a numerical algorithm for the efficient truncation of the Hilbert space of low-dimensional strongly correlated quantum systems based on a rather general decimation prescription. This algorithm has achieved unprecedented precision in the description of one-dimensional quantum systems. It has therefore quickly become the method of choice for numerical studies of such systems. Its applications to the calculation of static, dynamic, and thermodynamic quantities in these systems are reviewed here. The potential of DMRG applications in the fields of two-dimensional quantum systems, quantum chemistry, three-dimensional small grains, nuclear physics, equilibrium and nonequilibrium statistical physics, and time-dependent phenomena is also discussed. This review additionally considers the theoretical foundations of the method, examining its relationship to matrix-product states and the quantum information content of the density matrices generated by the DMRG.

http://www.physics.udel.edu/~bnikolic/QTTG/NOTES/DMRG/SCHOLLWOCK=RMP_dmrg.pdf

The density-matrix renormalization group

Recent studies on high-Tc superconductors have aroused new interest in tunnelling effects in unconventional superconductors. Unlike in conventional s-wave superconductors, the d-wave pairing state in these materials has an internal phase of the pair potential. The internal phase as a function of the wavevector of the Cooper pairs has a large influence on the electric properties of tunnelling junctions. Important effects of the internal phase on the Josephson current were first predicted theoretically. The idea has been established through several experiments using high-Tc Josephson junctions, which detect ?-phase shift between the a- and b-axis directions and fractional flux quanta. These results give convincing evidence for d-wave symmetry in high-Tc superconductors. In addition, the existence of new interference effects in the quasiparticle states near surfaces and boundaries has been suggested through theoretical predictions. Experimentally, a large number of tunnelling spectroscopy data showed zero-bias conductance peaks (ZBCPs), the origin of which cannot be explained in terms of the classical concept that a tunnelling conductance spectrum is a phase-insensitive probe of the electronic states. It is clarified theoretically that the observed ZBCPs reflect the formation of zero-energy states on the surface due to the ?-phase shift of internal phase in the d-wave pairing symmetry. The formulation developed for tunnelling spectroscopy suggests that tunnelling spectroscopy is essentially phase sensitive. In addition, the formation of the bound states has been shown to have a serious influence on the electrical properties of Josephson junctions. Several anomalous properties including strong enhancement of the Josephson current in the low-temperature region have been predicted theoretically. In this report, recent developments in tunnelling effects on surface bound states in unconventional superconductors are reviewed.

https://iopscience.iop.org/article/10.1088/0034-4885/63/10/202/pdf

Tunnelling effects on surface bound states in unconventional superconductors

We report a near-field microwave biosensor based on a dielectric resonator to detect glucose concentration. A microwave biosensor with a high Q dielectric resonator allows observation of the small variation of the glucose concentration by measuring the shift of the resonance frequency and the microwave reflection coefficient S(11). We observed the concentration of glucose with a detectable resolution up to 5 mgml at an operating frequency of about f=1.68 GHz. The change in the glucose concentration is directly related to the change in the reflection coefficient due to the electromagnetic interaction between the dielectric resonator and the glucose solution.

Microwave dielectric resonator biosensor for aqueous glucose solution

Effects of substrate temperature on copper(II) phthalocyanine thin films

Within a scattering framework, a theoretical study is presented for the spin-polarized quasiparticle transport in ferromagnet--$d$-wave-superconductor junctions with ${110}$ interface. We find that the subgap conductance behaviors are qualitatively different from a nonmagnetic case, due to the modification of Andreev reflection by the exchange field in the ferromagnet, and can also be significantly different from those of a ferromagnet--$s$-wave junction because of the sign change of the d-wave order parameter along the ${110}$ direction of the crystal. For a ballistic ferromagnet--$d$-wave-superconductor junction, a zero-bias conductance minimum is achieved. In addition, a conductance maximum at finite bias can also be evolved by interfacial scattering. For a normal-metal--ferromagnet--$d$-wave-superconductor junction, conductance resonances are predicted.

Spin-polarized quasiparticle transport in ferromagnet-d-wave-superconductor junctions with a 110 interface

Irreversible intermolecular reaction rates k in dilute polymer solutions and unentangled melts are studied as a function of time, molecular weight, and location of reactive groups along the polymer backbones. As for intramolecular reactions, the kinetics are determined by the reaction exponent 0 (3 + g)/z, where z and g are, respectively, the dynamical and excluded volume "correlation hole" exponents. Using scaling arguments, we show that k is driven to either mean-field (MF) or diffusion-controlled (DC) behavior, the short time rate k(t) being driven by increasing time, the long time rate k, by increasing chain length N. In parallel, detailed renormalization-group (RG) calculations of k are presented. The RG transformation drives the kinetics to either a DC or MF fixed point in correspondence to the scaling picture. In good solvents, dilute solutions (6 > 1) exhibit intrinsically MF reaction kinetics, irrespective of group reactivity. k is so weakened by intercoil excluded volume repulsions that the DC limit does not exist. Thus k - N-"g (v is the Flory exponent) scales as the equilibrium contact probability and for interior groups is related to the statistics of three-arm and four-arm star molecules. At small times k(t) exhibits only a weak time dependence. In contrast, unentangled melts (Rouse dynamics) are intrinsically DC (8 < 1) and k(t) - tl/*, k, - N-1/2 as derived by previous workers. We obtain crossover results describing the "trajectory" from MF to DC for moderately long chains. In 9 solvents (0 = 1) kinetics are marginal and characterized by logarithmic dependencies k(t) - l/ln t and k, - l/ln N. For reacting polymers of very different lengths k is dominated by the smallest chain in all cases.

Kinetics of Intermolecular Reactions in Dilute Polymer Solutions and Unentangled Melts

A simple Su-Schrieffer-Heeger-type model of ${\mathrm{C}}_{60}$ and doped ${\mathrm{C}}_{60}$ is presented The model is solved numerically in the adiabatic approximation In the half-filled case the cluster dimerizes, in agreement with experiment and more complicated calculations When an electron is added to half-filling, a polaron is present in the ground state This polaron possesses an unusual geometry; it is a loop circling the ${\mathrm{C}}_{60}$ cluster For two added electrons a bipolaron forms with a similar geometry It is suggested that this bipolaron may be observable in optical experiments

Barry Friedman

Papers

Microwave dielectric resonator biosensor for aqueous glucose solution

Effects of substrate temperature on copper(II) phthalocyanine thin films

Spin-polarized quasiparticle transport in ferromagnet-d-wave-superconductor junctions with a 110 interface

Kinetics of Intermolecular Reactions in Dilute Polymer Solutions and Unentangled Melts

Polarons in C60.