Atoms In Solid State Research Articles

Hybrid Quantum Systems with Artificial Atoms in Solid State

AbstractThe development of single‐platform qubits, predominant for most of the last few decades, has driven the progress of quantum information technologies but also highlighted the limitations of various platforms. Some inherent issues, such as charge/spin noise in materials hinder certain platforms, while increased decoherence upon attempts to scale up severely impacts qubit quality and coupling on others. In addition, a universal solution for coherent information transfer between quantum systems remains lacking. By combining one or more qubit platforms, one could potentially create new hybrid platforms that might alleviate significant issues that current single‐platform qubits suffer from, and in some cases, even facilitate the conversion of static to flying qubits on the same hybrid platform. While nascent, this is an area of rising importance that could shed new light on robust and scalable qubit development and provide new impetus for research directions. Here, the requirements for hybrid systems are defined with artificial atoms in the solid state, exemplified with systems that are proposed or attempted, and conclude with the outlook for such hybrid quantum systems.

Magnetic-free polarization rotation in an atomic vapor cell.

Magnetic-free nonreciprocal optical devices have attracted great attention in recent years. Here, we investigated the magnetic-free polarization rotation of light in an atom vapor cell. Two mechanisms of magnetic-free nonreciprocity have been realized in ensembles of hot atoms, including electromagnetically induced transparency and optically-induced magnetization. For a linearly polarized input probe light, a rotation angle up to 86.4° has been realized with external control and pump laser powers of 10 mW and is mainly attributed to the optically-induced magnetization effect. Our demonstration offers a new approach to realize nonreciprocal devices, which can be applied to solid-state atom ensembles and may be useful in photonic integrated circuits.

(Invited, Digital Presentation) Tuning the Electrodeposition of Actinides in Molten Alkali Halide Salts

Molten salts have found use as solvents in numerous applications including nuclear reactors, batteries, and the extraction and purification of various metals. Unfortunately, understanding of the chemistry of molten salt solutions is limited. In this presentation we explore the use of molten salts as a testbed for understanding both outer and inner coordination sphere effects on dissolved metal ions. The electron transfer reactions available to lanthanides (Eu3+, Sm3+, and Yb3+) and actinides (U3+, U4+, and Th4+) were explored in a series of alkali and alkaline earth halide salts. We present electrochemical data that demonstrate significant shifts in the reduction potentials of these metal ions as a function of the anion and cation identities of the molten salt solvent. We hypothesize that effects on the reduction potential of these metals come from two sources: (1) the primary coordination sphere and (2) the secondary coordination sphere. The influence from the primary coordination sphere is dominated by the degree of covalency in the coordination bonds between the Lnn+ and Ann+ cations and the molten salt anions. The influence of the secondary coordination sphere is dominated by the electron-withdrawing character of the salt cations. EXAFS data and computational results that support these hypotheses are presented. Further, we provide insight into electrodeposition of the An0 metals under these conditions and highlight temperature and molten salt effects that influence these electrodepositions. Specifically, we propose that increased mobility of solid-state atoms at high temperature (> 800°C) influence the properties of electrodeposited metals.

Quantum Multipartite correlation in Optical channel

The communication in the quantum networks is based on optical channels to take the advantage of analog, optical and digital communication system. Single data which carries information over the channel can be termed as solid state atoms or photons. The reliable channel is the one which carries the same state from the sending node to destination there can be superposition of states. practically ideal channel does not exist, the optical Gaussian channel which is considered as a degradable quantum channel. The optical interfaces and standard signal format would allow interconnecting fiber optic transmission equipment through multiple networks which carries information generated by multiple users of the network. Taking the infrastructure of existing telecommunication use the quantum information so that it is secure by its nature.

Ultrabright single-photon sources

The development of a quantum communication network will require sources that efficiently emit single photons. Now, using a new lithography technique that garnered a silver CNRS medal in 2014, it has recently proved possible to fabricate these sources using quantum dots (QDs), that is, artificial solid-state atoms. Performed at cryogenic temperatures, this technique makes it possible to position a single QD in the middle of an optical microcavity with nanometric precision.

Stabilization of body-centred cubic iron under inner-core conditions

The Earth’s solid core is mostly composed of iron. However, despite being central to our understanding of core properties, the stable phase of iron under inner-core conditions remains uncertain. The two leading candidates are hexagonal close-packed and body-centred cubic (bcc) crystal structures, but the dynamic and thermodynamic stability of bcc iron under inner-core conditions has been challenged. Here we demonstrate the stability of the bcc phase of iron under conditions consistent with the centre of the core using ab initio molecular dynamics simulations. We find that the bcc phase is stabilized at high temperatures by a diffusion mechanism that arises due to the dynamical instability of the phase at lower temperatures. On the basis of our simulations, we reinterpret experimental data as support for the stability of bcc iron under inner-core conditions. We suggest that the diffusion of iron atoms in solid state may explain both the anisotropy and the low shear modulus of the inner core. The crystal structure of iron under the extreme pressures and temperatures of Earth’s core is debated. Numerical simulations suggest that the body-centred cubic structure of iron is stable under inner-core conditions.

An Eectrochemical Investigation on Additives to the Controllable Electro-Healing Cracks in Nickel

Healing or repairing cracks in materials is highly desired not only from economic considerations but also for their sustainable and reliable applications. For metallic materials, crack healing is challenging due to the limited mobility of metallic atoms in solid state at ambient temperature. Recently, it is reported1 that an electrochemical process named electro-healing is capable of repairing through-thickness cracks in nickel where metallic ions in electrolytes were introduced as the healing agent. However, in plain healing solutions when there is no additives, the healing crystals grow following a general mode, in which the healing crystals grow oppositely from the two sidewalls of the crack towards the meeting line (plane), where randomly-located micrometer-sized voids or smaller are sometimes observed, see Fig.1 (a). As these voids are detrimental to the load-bearing ability of the healed crack, it is essential to control the growth of the healing crystals to minimize the number of voids that left after electro-healing2. It is well-established that the addition of inhibitors or accelerators to an electrolyte is capable of suppressing or accelerating the metal deposition rate. In the present work, two inhibitors: polyethyleneimine (PEI) and 2-mercapto-5-benzimidazolesulfonic acid (MBIS), and an accelerator thiourea (TU) were added respectively to the conventional Watts bath to investigate the controllable electro-healing on pure Ni plate with a through thickness crack. Rotating disk electrode (RDE) was introduced to evaluate the electrochemical behavior in crack tips and crack center. Voltammograms and galvanostatic measurements were carried out to evaluate the inhibition effect of PEI, MBIS, synergistic effect of MBIS+TU to the reduction of Ni ions. The cathodic current efficiency was also investigated. SEM observations were used to characterize the morphology of the healed cracks. It is demonstrated that the addition of PEI greatly inhibited the reduction of Ni ions. This inhibition is convection dependent. As a result, the growth of healing crystals from the sidewalls was much restricted compared to that from the crack tips((ν s <<ν t ) when strong convection was employed to the solution. No meeting line was observed in the healed crack, instead, annual-rings and some large visible defects were found in the healed crack(Fig.1(b)). The former is believed to be the results of fluctuation of PEI diffusion flux, while the latter is attributed to the hydrogen inclusion corresponding the much reduced current efficiency. MBIS exhibited a similar inhibit effect to Ni reduction to PEI when added to the Watts bath. The surface adsorption kinetics of MBIS is also controlled by transportation. The difference is that the solution with MBIS demonstrated much higher current efficiencies compared with PEI when similar amount of inhibitor were added(100µM). For example, at a current density of 1 A/dm2, the current density of solution with PEI is about 70 %, while that with MBIS is about 97 % when the rotation speed of RDE is 50 rpm. Consequently, except annual rings, no visible defects were spotted in the acquired morphology (Fig.1(c)). From the linear sweep voltammetry (LSV), it is observed that as an accelerator, the addition of TU to the MBIS containing solution demonstrated a depolarization effect to the Ni reduction,the growth of healing crystals from sidewalls was much enhanced when TU was presented. A meeting line appeared again(Fig.1(d)). But different from that of plain solution without additives, there is no voids or pores left along the meeting line after electro-healing. Instead of that perpendicular to the meeting line, the healing crystals grew at an acute angle to the meeting line, which is believed to be the consequence of simultaneous growth from crack sidewalls and the crack tip. It is expected that a satisfactory recovery of load bearing ability will be accomplished after the controllable electro-healing with the co-addition of both MBIS and TU. Fig. 1 SEM morphologies of cracks after electro-healing in different solutions: (a) Plain Watts bath without additives(general growth mode); (b) 35µM PEI, (c) 50µM MBIS and (d) combination of 50µM MIBS and 20µM TU. Black arrows indicate the growth direction of the healing crystals, white arrows in (a) indicate pores and voids. White dot-dashed line in (a) and (d) designates the meeting line. Watts bath contains: 1M NiSO4•6H2O, 0.2 M NiCl2•6H2O and 0.5 M H3BO3.Ref.X.G. Zheng, Y.N. Shi and K. Lu, Materials Science & Engineering A, 561, 52 (2013).X.G. Zheng, Y.N. Shi and K. Lu, J. Electrochem. Soc.,160, D289(2013)

Optimal irreversible stimulated emission

We studied the dynamics of an initially inverted atom in a semi-infinite waveguide, in the presence of a single propagating photon. We show that atomic relaxation is enhanced by a factor of 2, leading to maximal bunching in the output field. This optimal irreversible stimulated emission is a novel phenomenon that can be observed with state-of-the-art solid-state atoms and waveguides. When the atom interacts with two one-dimensional electromagnetic environments, the preferential emission in the stimulated field can be exploited to efficiently amplify a classical or a quantum state.

Fabrication technology of and symmetry breaking in superconducting quantumcircuits

Superconducting quantum circuits are promising systems for experiments testingfundamental quantum mechanics on a macroscopic scale and for applications inquantum information processing. We report on the fabrication and characterization ofsuperconducting flux qubits, readout dc SQUIDs, on-chip shunting capacitors, andhigh-quality coplanar waveguide resonators. Furthermore, we discuss the tunability andfundamental symmetry aspects inherent to all superconducting qubits, whichcan be regarded as artificial solid-state atoms. Comparing them to their naturalcounterparts, we discuss first- and second-order energy shifts due to static controlfields. Additionally, we present an intuitive derivation of the first- and second-ordermatrix elements for level transitions in the presence of coherent microwave driving.

Real-Time Observation of Tubule Formation from Amorphous Carbon Nanowires under High-Bias Joule Heating

The tubule formation process from amorphous carbon nanowires under high-bias-caused Joule heating was observed in real time in a high-resolution transmission electron microscope. The crystallization of the amorphous carbon nanowires occurred in two distinct ways: the formation of tubular graphitic basal planes parallel to the nanowire axis on the surface and the formation of nano-onions in the interior of the nanowire. The tubule formation mechanism is a process of solid-state atom diffusion at high temperatures. Energetically, the tubule formation is caused by the exceptionally low surface energy of the (0002) plane of graphite. Higher input power to the amorphous nanowires generally leads to improved graphitization and, in turn, to increased conductance. The results suggest that nanotube formation in the arc-discharge growth process may involve the formation and crystallization of amorphous carbon.

Configuration and conformational equilibrium of (±)- trans-1-oxo-3-thiophen-2-yl-isochroman-4-carboxylic acid methyl ester

The X-ray analysis of 1-oxo-3-thiophen-2-yl-isochroman-4-carboxylic acid methyl ester 1 confirmed its trans-configuration and a conformation with diaxial H-3 and H-4 atoms in solid state. NMR experiments indicated that trans- 1 exists in solution in both expected conformers. In CDCl 3 and especially in CD 3OD or DMSO, the conformational equilibrium is shifted towards the conformer with diequatorial H-3 and H-4, which was also determined by 2D NOESY experiments. The shift is due to the greater polarity of that conformer deduced by ab initio calculations.

Solid-state halogen atom source for chemical dynamics and etching

We describe a solid-state Br atom source for surface etching, kinetics, and reaction dynamics studies. Pulsed laser irradiation of crystalline KBr, near the bulk absorption threshold at 6 eV, produces hyperthermal Br atoms in dense plumes. The Br atom density and velocities may be controlled by choice of laser pulse power and photon energy. Single and multiple pulse excitation of KBr produces Br and Br* in controllable quantities and velocities, thus providing an attractive ultrahigh vacuum compatible solid-state radical atom source. The solid-state atom source is in principle extendable to other halogens using other alkali halides and perhaps other materials.

Application of Band Parameters to Materials Design.

Availability of the two band parameters to materials design is reviewed. In order to express the chemical character between two different atoms in solid state, the concept of two band parameters for any bond between two different atoms is proposed on the basis of the bond orbital model and the empirical relation between observed band gap and pseudopotential radii of Zunger. The two band parameters are called as the hybrid function (H) and gap reduction parameter (S), which substantially correspond to the energy difference between the bonding and anti-bonding levels and the band widening effect due to the formation of crystalline state. These parameters roughly correspond to ionic and covalent band gaps which are constructed by one gap model. By comparing with the definition of ionicity based on the ionic and covalent band gaps, it is found that the ionicity for any A–B bond can be estimated from the two band parameters. Extensive availability of the band parameters to materials design is suggested by exemplifying several successful results such as the construction of crystal structure maps for compounds, determination of site preference of third alloying elements in intermetallics and prediction of phase changes in pseudobinary nitride films in the energetic processes.

Quantum nonlinear resonance and quantum chaos in Aharonov-Bohm oscillations in mesoscopic semiconductor rings

We consider Aharonov-Bohm oscillations in a mesoscopic semiconductor ring threaded by both a constant magnetic flux and a time-dependent, resonant magnetic field with one or two frequencies. Working in the ballistic regime, we establish that the theory of ``quantum nonlinear resonance'' applies, and thus that this system represents a possible solid-state realization of ``quantum nonlinear resonance'' and ``quantum chaos.'' In particular, we investigate the behavior of the time-averaged electron energy at zero temperature in the regimes of (i) an isolated quantum nonlinear resonance and (ii) the transition to quantum chaos, when two quantum nonlinear resonances overlap. The time-averaged energy exhibits sharp resonant behavior as a function of the applied constant magnetic flux, and has a staircase dependence on the amplitude of the external time-dependent field. In the chaotic regime, the resonant behavior exhibits complex structure as a function of flux and frequency. We compare and contrast the quantum chaos expected in these mesoscopic ``solid-state atoms'' with that observed in Rydberg atoms in microwave fields, and discuss the prospects for experimental observation of the effects we predict.

Non-Kondo prediction of Wilson ratio for heavy fermion systems

Abstract We propose a new two-electron band theory approach to treat correlated f-electron systems. This involves: first, an exact two-body treatment of the local correlations for a ‘solid-state atom’, i.e. non-spherical local environment of a cerium (or other pertinent) nucleus; then, turning on the interactions giving extended two-electron states (bands). This approach treats the hybridization and exchange Coulomb interaction effects within this two-body treatment on an equal footing. Without invoking the concept of Kondo resonance, it provides a non-magnetic singlet state competing, side by side with other, magnetic states. It explains the wide diversity in f magnetism and the heavy fermion phenomenology, including the specific heat and susceptibility, and most significant, provides an absolute prediction of the Wilson ratio, reproducing the experimental scale and trend in change of the Wilson (low-temperature susceptibility to specific heat) ratio on going from non-magnetic to magnetic heavy fermion m...

Impact parameter dependence of the electronic energy loss of low- and intermediate-energy protons in collisions with solid state atoms

Using the linear-response dielectric theory and local electron density approximation, we calculate the electronic energy loss of low- and intermediate-energy protons in collision with a solid atom as a function of the impact parameter. In these studies, the correlation and exchange interaction of the electron gas in solids is taken into consideration by using a local field correction dielectric function. Based on the formalism electronic stopping cross-sections of protons in solids are calculated, and the results are compared with experimental data and empirical results, as well as with other previous theoretical results.

Solid-state 31P [formula omitted] NMR vs. solution study of bis(tertiary phosphines)

Solid-state 31P and 13C CP MAS results of several diphosphines are compared with solution phase data. Non-equivalence of the P atoms are observed in the solid state for the less flexible derivatives (including all chiral diphosphines studied), whereas the more flexible compounds with a linear alkyl chain such as the 1,2-ethane and the 1,4-butane derivatives give only rise to a single resonance. For the more strained bis(diphenylphosphino)methane contradictory data have been reported. Our experiments confirm the existence of an AB spin system, i.e., two different P atoms in solid state. Substantial chemical shift difference between P atoms have been observed in the solid state but not in solution of the chiral compounds. A possible explanation is suggested in terms of the concerted anisotropic effect of the phenyl rings attached to the phosphorus atom.

Interatomic potential in solids and its applications to range calculations

Abstract Using the Gordon-Kim statistical model, the hetero-nuclear potentials have been numerically evaluated from the first principle for variousZ 1—Si combinations, where the charge distribution of the solid-state atom is constructed from the charge density of the Dirac-Hartree-Fock-Slater gas-state atom. The corresponding projected ranges in silicon are calculated using the Monte Carlo simulation code ACAT. For e = 0.09 the calculated ranges show a little weaker Z1 oscillation than the experimental data, but they reproduce reasonably the experimental projected ranges. The convenient combination rule for constructing the hetero-nuclear potential from the corresponding homo-nuclear potentials is proposed. This combination rule is shown not only to reproduce well the hetero-nuclear potential which is calculated from the first principle, but also to yield the reasonable projected range. The analytic universal function is also proposed averaging the various homo-nuclear potentials, and it is found that the...

Kinetics of the thermal decomposition of kyanite

Abstract The kinetics of the solid state high-temperature transformation of kyanite (Al2SiO5Al2O3·SiO2) powders (≤40 μm) to 3:2-mullite (3Al2O3·2SiO2) and silica (SiO2 were investigated by means of quantitative X-ray diffraction techniques. The transformation interval was found to lie between about 1150 and 1350°C. The reaction law best fitting the kinetic data is: 1-α = kta. The transformation is believed to be reconstructive, with decomposition of the kyanite structure, solid-state atom diffusion, and (epitactic) rearrangement of mullite and cristobalite. Cristobalite represents part of the ⪡free⪢ silica, the rest being present as a glassy phase. Addition of Fe2O3 and TiO2 to the starting material exerts a marked decrease of the transformation temperature, with TiO2 having a somewhat stronger influence than Fe2O3. The reason may be an oxide-catalyzed reaction; the decomposition begins at nuclei formed at the surfaces of the kyanite particles, which are coated with thin layers of hematite and rutile respectively.

Kinetics of the thermal decomposition of kyanite

The kinetics of the solid state high-temperature transformation of kyanite (Al 2SiO 5Al 2O 3·SiO 2) powders (≤40 μm) to 3:2-mullite (3Al 2O 3·2SiO 2) and silica (SiO 2 were investigated by means of quantitative X-ray diffraction techniques. The transformation interval was found to lie between about 1150 and 1350°C. The reaction law best fitting the kinetic data is: 1-α = kt a. The transformation is believed to be reconstructive, with decomposition of the kyanite structure, solid-state atom diffusion, and (epitactic) rearrangement of mullite and cristobalite. Cristobalite represents part of the ⪡free⪢ silica, the rest being present as a glassy phase. Addition of Fe 2O 3 and TiO 2 to the starting material exerts a marked decrease of the transformation temperature, with TiO 2 having a somewhat stronger influence than Fe 2O 3. The reason may be an oxide-catalyzed reaction; the decomposition begins at nuclei formed at the surfaces of the kyanite particles, which are coated with thin layers of hematite and rutile respectively.