Numerical simulations of previous plane shock wave measurements on highly oriented pyrolytic graphite (HOPG), shocked to four peak stresses ranging from 27 to 50 GPa, are presented to address a long-standing question: When is the diamond phase formed in the shock-compressed graphite to diamond trans...

[Phys. Rev. B 87, 174104] Published Fri May 17, 2013

We report a first-principles investigation of magnetic excitations in a compensated half-metallic ferrimagnet using both the adiabatic Heisenberg model and the dynamic spin susceptibility of the electronic system. The combination of half-metallicity and spin compensation of inequivalent magnetic sub...

[Phys. Rev. B 87, 174420] Published Fri May 17, 2013

We compute the field-angle-resolved specific heat and thermal conductivity using realistic model band structures for the heavy-fermion superconductor CeCoIn₅ to identify the gap structure and location of nodes. We use a two-band tight-binding parametrization of the band dispersion as input for the s...

[Phys. Rev. B 87, 174514] Published Fri May 17, 2013

We present a study of the structural and physical properties of directly hole-doped LaFe_1−xMn_xAsO (x=0.0−0.2) and the influence of charge compensation by additional F doping in LaFe_0.9Mn_0.1AsO_1−yF_y (y=0.1−0.5). High-quality polycrystalline samples were prepared for Mn-doped LaFe_1−xMn_xAsO and the low...

[Phys. Rev. B 87, 174515] Published Fri May 17, 2013

We study theoretically how the dynamics of the resistive state in narrow superconducting channels shunted by an external resistor depends on channel's length L, the applied current j, and parameter u characterizing the penetration depth of the electric field in nonequilibrium superconductors. We sho...

[Phys. Rev. B 87, 174516] Published Fri May 17, 2013

An in-situ investigation from high-resolution neutron powder diffraction data on the structural evolution of TmNiO₃ and YbNiO₃ perovskites across the metal-insulator transition, with T_MI = 596 K and 598 K, respectively, allowed the charge disproportionation effect that these perovskites experience u...

[Phys. Rev. B 87, 184111] Published Fri May 17, 2013

The performance of advanced magnetic tunnel junctions built of ferromagnetic (FM) electrodes and MgO as an insulating barrier depends decisively on the properties of the FM/insulator interface. Here we investigate interface formation between the Co-based Heusler compound Co₂MnSi (CMS) and MgO by mea...

[Phys. Rev. B 87, 184418] Published Fri May 17, 2013

The fabrication of high-quality thin superconducting films is essential for single-photon detectors. Their device performance is crucially affected by their material parameters, thus requiring reliable and nondestructive characterization methods after the fabrication and patterning processes. Import...

[Phys. Rev. B 87, 184507] Published Fri May 17, 2013

We report the detailed electronic structure of a hole-doped delafossite oxide CuCr_1−xMg_xO₂ (0≤x≤0.03) studied by photoemission spectroscopy (PES), soft x-ray absorption spectroscopy (XAS), and band-structure calculations within the local-density approximation +U (LDA+U) scheme. Cr/Cu 3p-3d resonant ...

[Phys. Rev. B 87, 195124] Published Fri May 17, 2013

The plane-wave density functional theory code CASTEP was used with the Tkatchenko-Scheffler van der Waals correction scheme and the generalized gradient approximation of Perdew, Burke, and Ernzerhof (GGA PBE) to calculate the binding energy of Au, Cr, and Al atoms on the armchair and zigzag edge bin...

[Phys. Rev. B 87, 195430] Published Fri May 17, 2013

We investigate the effect of strain-induced gauge fields on statistical distribution of energy levels of triangular graphene nanoflakes with zigzag edges. In the absence of strain fields but in the presence of weak potential disorder such systems were found by Rycerz [ Phys. Rev. B 85 245424 (2012)...

[Phys. Rev. B 87, 195431] Published Fri May 17, 2013

We show that the functional renormalization group is a numerically cheap method to obtain the low-energy behavior of the Anderson impurity model describing a localized impurity level coupled to a bath of conduction electrons. Our approach uses an external magnetic field as the flow parameter, partia...

[Phys. Rev. B 87, 201107] Published Fri May 17, 2013

We use scanning tunneling microscopy to determine the surface structure and dopant distribution in Pr_xCa_1−xFe₂As₂, the highest-T_c member of the 122 family of iron-based superconductors. We identify the cleaved surface termination by mapping the local tunneling barrier height, related to the work fun...

[Phys. Rev. B 87, 201108] Published Fri May 17, 2013

Recently demonstrated solid-state single-electron sources generate different quantum states depending on their operation condition. For adiabatic and nonadiabatic sources, we determine the Glauber correlation function in terms of the Floquet scattering matrix of the source. The correlation function ...

[Phys. Rev. B 87, 201302] Published Fri May 17, 2013

We present first-principles calculations of the quasiparticle band structures of four isostructural semiconducting metal chalcogenides A₂B₃ (with A = Sb, Bi and B = S, Se) of the stibnite family within the G₀W₀ approach. We perform extensive convergence tests and identify a sensitivity of the quasip...

[Phys. Rev. B 87, 205125] Published Fri May 17, 2013

We analyze the characteristics of polarity in unsupported nanoribbons with zigzag edges, by a combination of analytic models, semiempirical Hartree-Fock simulations, and first-principles approach. We consider two materials with widely different ionic-covalent character, MgO and MoS₂, and two polarit...

[Phys. Rev. B 87, 205423] Published Fri May 17, 2013

We report a strategy to induce superconductivity in the BiS₂-based compound LaOBiS₂. Instead of substituting F for O, we increase the charge-carrier density (electron dope) via substitution of tetravalent Th⁺⁴, Hf⁺⁴, Zr⁺⁴, and Ti⁺⁴ for trivalent La⁺³. It is found that both the LaOBiS₂ and ThOBiS₂ pa...

[Phys. Rev. B 87, 174512] Published Thu May 16, 2013

We study quantum phase-slip (QPS) processes in a superconducting ring containing N Josephson junctions and threaded by an external static magnetic flux Φ_B. In such a system, a QPS consists of a quantum tunneling event connecting two distinct classical states of the phases with different persistent c...

[Phys. Rev. B 87, 174513] Published Thu May 16, 2013

We study the effects of spin-orbit interaction (SOI) on the current-induced motion of a magnetic (Bloch) domain wall in ultrathin ferromagnetic nanowires. The conspiracy of spin relaxation and SOI is shown to generate a strong nonequilibrium Rashba field, which can dominate even for weak SOI. This f...

[Phys. Rev. B 87, 184415] Published Thu May 16, 2013

The weak ferromagnetic moment in Ni-doped CuB₂O₄ can be rotated by applying an electric field. While this implies spin-driven ferroelectricity, no direct evidence of electric polarization has been reported to date. Here we report the induction and control of polarization in the borate in the presenc...

[Phys. Rev. B 87, 184416] Published Thu May 16, 2013

The strength of perpendicular anisotropy is known to drive the spin reorientation in thin magnetic films. Here, we consider the effect different order anisotropies have on two phase transitions: the spin reorientation and the orientational order transitions. We find that the relative magnitude of di...

[Phys. Rev. B 87, 184417] Published Thu May 16, 2013

Dynamic Hubbard models are extensions of the conventional Hubbard model that take into account the fact that atomic orbitals expand upon double occupancy. It is shown here that systems described by dynamic Hubbard models have a tendency to expel negative charge from their interior to the surface and...

[Phys. Rev. B 87, 184506] Published Thu May 16, 2013

We report numerical and experimental investigations into modulation instability in a nonlinear magnetoinductive waveguide. By numerical simulation we find that modulation instability occurs in an electrical circuit model of a magnetoinductive waveguide with third-order nonlinearity. We fabricate the...

[Phys. Rev. B 87, 195123] Published Thu May 16, 2013

We develop a nonlocal dielectric-response theory to describe the temperature dependence of exciton lifetime in metal-semiconductor heterostructures. Coupling between excitons and surface plasmons results in a strongly nonmonotonous behavior of exciton decay rate versus temperature, affected by surfa...

[Phys. Rev. B 87, 195429] Published Thu May 16, 2013

Site-controlled quantum dots formed during the deposition of (Al)GaAs layers by metal-organic vapor-phase epitaxy on GaAs(111)B substrates patterned with inverted pyramids result in geometric and compositional self-ordering along the vertical axis of the template. We describe a theoretical scheme th...

[Phys. Rev. B 87, 205422] Published Thu May 16, 2013

When magnetic nanoparticles (MNPs) are single domain and magnetically independent, their magnetic properties and the conditions to optimize their efficiency in magnetic hyperthermia applications are now well understood. However, the influence of magnetic interactions on magnetic hyperthermia propert...

[Phys. Rev. B 87, 174419] Published Wed May 15, 2013

[Phys. Rev. B 87, 179905] Published Wed May 15, 2013

[Phys. Rev. B 87, 179906] Published Wed May 15, 2013

Many electronic systems (e.g., the cuprate superconductors and heavy fermions) exhibit striking features in their dynamical response over a prominent range of experimental parameters. While there are some empirical suggestions of particular increasing length scales that accompany such transitions in...

[Phys. Rev. B 87, 184202] Published Wed May 15, 2013

First-principles density functional theory DFT+U calculations and experimental neutron diffraction structure analyses were used to determine the low-temperature crystallographic and magnetic structure of bixbyite α-Mn₂O₃. The energies of various magnetic arrangements, calculated from first principle...

[Phys. Rev. B 87, 184413] Published Wed May 15, 2013