Strong Correlations and Superconductivity in the Supermoiré Lattice

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Electronic correlations beyond static mean-field theories are of fundamental importance in describing the properties of complex materials—such as transition-metal oxides—where the low-energy physics is driven by localized d or f electrons. Here, we show that it is possible to capture these correlations with a local and dynamical self-energy, extending to the spin-polarized and multisite case in our recently introduced dynamical Hubbard functional formulation. We apply this formalism to the prototypical tran

The structure and transport of electrolytes in nanoscale channels are known to be affected by the electronic properties of the confining walls. This influence is particularly pronounced in quasi-one-dimensional nanotubes, where the high surface-to-volume ratio makes the wall the dominant source of electrostatic screening. For instance, ideal metallic tubes suppress long-range Coulomb interactions between ions exponentially. Yet, there exists no generic framework for evaluating electrostatic interactions in

Strong magnetic fields applied to metals confine electrons into Landau orbits, except at the boundaries at which frequent surface collisions disrupt their cyclotron motion. In two-dimensional systems, these boundary states form dissipationless chiral edge channels in the quantum Hall regime. By contrast, the quantum limit of three-dimensional (3D) metals is traditionally thought to differ fundamentally and instead contains gapless Landau bands, lacking quantized Hall conductance or dissipationless transport

Quantum Signal Processing (QSP), a framework for implementing matrix-valued polynomials, is a fundamental primitive in various quantum algorithms. Despite its versatility, a potentially underappreciated challenge is that all systematic protocols for implementing QSP rely on post-selection. This can impose prohibitive costs for tasks when amplitude amplification cannot sufficiently improve the success probability. For example, in the context of ground-state preparation, this occurs when using a too poor init

We predict that broken-gap InAs/GaSb core/shell nanowires, when operating in the topological insulating regime, undergo a collapse of the hybridization gap under the application of a transverse electric field. We perform predictive, self-consistent k p calculations for realistic nanostructures and show that a gap closure occurs at two Kramers-related, massless Dirac points at a critical value of the field in the V/,a range. An analysis based on the Bernevig-Hughes-Zhang model shows that the new

For bioelectronic applications, the optimal electronic device is one capable of effectively interfacing with living systems by coupling electronic conduction and the ionic conduction which underlies signal transmission in physiological environments. In this context, the organic electrochemical transistor (OECT), which has a conjugated polymer‐based active channel, is a promising device since the conjugated polymer can feature mixed ionic‐electronic conduction in aqueous electrolytes. Having gained a solid u

Accurate determination of physiological states of cellular metabolism requires detailed information about metabolic fluxes, metabolite concentrations and distribution of enzyme states. Integration of fluxomics and metabolomics data, and thermodynamics-based metabolic flux analysis contribute to improved understanding of steady-state properties of metabolism. However, knowledge about kinetics and enzyme activities though essential for quantitative understanding of metabolic dynamics remains scarce and involv

The idea that a quantum magnet could act like a liquid crystal, breaking spin-rotation symmetry without breaking time-reversal symmetry, holds an abiding fascination. However, the very fact that spin nematic states do not break time-reversal symmetry renders them "invisible" to the most common probes of magnetism - they do not exhibit magnetic Bragg peaks, a static splitting of lines in NMR spectra, or oscillations in μSR. Nonetheless, as a consequence of breaking spin-rotation symmetry, spin-nematic states

investigate the use of MOVPE-grown ordered nanostructures on non-planar substrates for quantum nano-photonics and quantum electrodynamics-based applications. The mastering of surface adatom fluxes on patterned GaAs substrates allows for forming nanostrucutres confining well-defined charge carrier states. An example given is the formation of quantum dot (QD) molecules tunneled-coupled by quantum wires (QWRs), in which both electron and hole states are hybridized. In addition, it is shown that the high degree

Defect levels of dangling bonds in silicon and germanium are determined within their respective band gaps through the use of hybrid density functionals. To validate our approach, we first considered the dangling bond in silicon finding two well-separated defect levels in excellent correspondence with their experimental location. Application to the dangling bond in germanium then yields two very close defect levels lying just above the valence band, which is consistent with the experimental location of the c

Using a density functional approach, we study structural and electronic properties of the 4H(0001)-SiC/SiO2 interface. Through the sequential use of classical and ab initio simulation methods, we generate an abrupt model structure which describes the transition between crystalline SiC and amorphous SiO2 without showing any coordination defect. The first step in our generation procedure consists in identifying suitable interfacial bonding patterns which account for the bond density reduction across the inter

We present scanning tunneling microscopy (STM) measurements at the TaSe2 surface showing a first order process leading to a surface Mott transition. This metal to insulator transition is triggered by the commensurate charge density wave (CDW) which set up at 475 K. The electronic structure rearrangement due to the new periodicity gives rise to a half filled sub-band prone to the localization phenomena. This transition results fully developed below 250K in agreement with previous photoemission Measurements.

Retarding field analyzers (RFAs) are essentially the only practical tool with which to measure the distribution of ion energies in the boundary plasma of magnetic fusion devices. The technique has long been attempted in such facilities with varying degrees of success, but, by virtue of the delicate nature of these material probes and the hostile environment in which they are inserted, its use has been limited to smaller plasma machines with easier access and more tolerable plasma conditions. This article de

We investigate structural, electronic, dynamical, and dielectric properties of zircon (ZrSiO4) within density-functional theory. The atomic structure is fully relaxed and the structural parameters are found to differ by less than 1.5% from the experimental data. The associated electronic band structure and density of states are also presented. Using density-functional perturbation theory, we obtain the phonon frequencies at the center of the Brillouin zone, the Born effective charge tensors, and the dielect

The dimerization energies of two M2+ to give M42+ (M = S, Se) were calcd. They depend strongly on the size of the basis set and the correlation method used (ranging from 217 to 522 kJ/mol, M = S) and, therefore, a systematic study of basis set and correlation effects was performed [MP2, MP3, MP4(SDQ), CCSD, CCSD(T)]. The introduction of a second set of polarizing d-functions caused a significant redn. of the dimerization energies, but neither of the above limits is reached by the MPn (n = 2, 3, 4) theory, e

This thesis is concerned with the theoretical study of the transport in small conductors at low temperatures. Our aim is to elucidate the interplay between the statistical environment and mesoscopic systems, and its effect on electronic features in the domain of transport. In a first phenomenological approach based on the Landauer picture of transport, we study de transport properties of a mesoscopic sample connected to electronic reservoirs. The influence of the coupling to the statistical environment on t

We present here measurements on hexagonal cavities that have areas between 2.0 and 8.6 mu m/sup 2/. The 2D triangular lattice PBG mirrors are etched into a GaAs/AlGaAs waveguide heterostructure with 3 layers of InAs quantum dots at the centre of a 240 nm thick GaAs core. The photoluminescence of the InAs dots internally probes the cavity resonances and the small fraction of light that is scattered into air is collected and fed to an optical multichannel analyser. The hexagonal cavities defined by 2D photoni

The temperature-dependent damping of quantum-mechanical interference patterns from surface-state electrons scattering off steps on Ag(111) and Cu(111) has been studied using scanning tunneling microscopy (STM) and spectroscopy in the temperature range 3,5-178 K. The thermal damping of the electron standing waves is described quantitatively within a simple plane-wave model accounting for thermal broadening due to the broadening of the Fermi-Dirac distributions of sample and tip, for beating effects between e

The electronic states in the conduction and valence bands of quantum wires are studied by means of the effective mass hamiltonian and the Luttinger hamiltonian. The band mixing effects due to the wire geometry are fully taken into account by an accurate finite element solution of the resulting Schrodinger equations. The quantum wire profiles measured by transmission electron microscopy are used. The comparison of theoretical results with photoluminescence excitation spectra of various nanostructures yields

Ion-bombarded polystyrene with a 0.5-keV Ar+ beam has been investigated by means of photoelectron spectroscopy performed with synchrotron radiation. After a dose of 10(15) ions/cm2 the evolution of the valence band of the bombarded sample towards an amorphous carbonlike configuration is reported. From the analysis of valence-band spectra we estimated the out-diffusion of hydrogen and showed that its electronic states remain well identified and stable until the hydrogen presence is about 35% with respect to

Strong Correlations and Superconductivity in the Supermoiré Lattice

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Basis set and correlation effects in the calculation of accurate gas phase dimerization energies of two M2+ to give M42+ (M = S, Se)

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