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![Crystal structure of Bismuth of A7, α-arsenic type structure, in the hexagonal setting.: The unit cell is represented as a grey box, with the layer stacking developing along [001].](publication/281680739/figure/fig1/AS:282464149884930@1444356109149/Crystal-structure-of-Bismuth-of-A7-a-arsenic-type-structure-in-the-hexagonal-setting.png)
Crystal structure of Bismuth of A7, α-arsenic type structure, in the hexagonal setting.: The unit cell is represented as a grey box, with the layer stacking developing along [001].
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Materials with strong spin-orbit coupling, which competes with other particle-particle interactions and external perturbations, offer a promising route to explore novel phases of quantum matter. Using LDA + DMFT we reveal the complex interplay between local, multi-orbital Coulomb and spin-orbit interaction in elemental bismuth. Our theory quantifie...
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... crystallises in the A7, α-arsenic type structure (Fig. 1). In the rhombohedral setting, the unit cell contains two atoms. As homologue P and As, A7 Bi is characterised by extended puckered layers of three-connected Bi atoms, with shorter distances within each layer than between (111) layers. In Bi however, the difference between the two sets of distances is reduced, such that layered A7 Bi is ...
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Citations
... As we can see, the R-3m structure is the ground state of BiP, SbN and SbP, and is also one of the low-energy structures of BiN. It is noteworthy that the R-3m structure is isostructural to the gray arsenic A7 structure, which is rhombohedral and consists of the ABC stacking of the V-V layers [38,39], as shown in figures 2(a) and (d). Each V-V monolayer has a puckered honeycomb lattice as shown in figure 2(c), which is similar to the monolayer of blue phosphorus. ...
The III-V binary compound semiconductors such as GaN, GaP, InN and InP have extensive applications in various optoelectronic, microwave and power-electronic devices. Using first-principles calculation, we systematically studied the structural and electronic properties of the V-V binary compounds (BiN, BiP, SbN and SbP) that are isoelectronic to GaN, GaP, InN and InP if Bi and Sb are in the +3 valence state. Interestingly, we found that the ground-state structures of BiP, SbN and SbP have the R-3m symmetry and are isostructural to the layered structure of gray arsenic, whereas BiN prefers a different ground-state structure with the C2 symmetry. Electronic structure calculations showed that the bulk BiN is a narrow bandgap semiconductor for its bandgap is about 0.2 eV. In contrast, BiP, SbN and SbP are metallic. The layered ground-state structure of the V-V binary compounds motivates us to study the electronic properties of their few-layer structures. As the structure becomes monolayer, their bandgaps increase significantly and are all in the range from about 1 eV to 1.7 eV, which are comparative to the bandgap of the monolayer gray arsenic. The monolayer BiP, SbN and SbP have indirect bandgaps, and they show a semiconductor-metal transition as the number of layers increase. Interestingly, the monolayer BiP has the largest splitting (350 meV) of the CBM valley, and thus may have potential application in novel spintronics and valleytronics devices.
... A very recent work by Koley, Laad and Taraphder [21] that followed heels of experimental discovery, offers an exciton fluctuation mediated mechanism of superconductivity in Bi. In an attempt to understand normal state properties of Bi quantitatively, Craco and Leoni [22] have emphasized importance of using a moderate Hubbard U in the 6p orbitals of Bi. ...
... From band theory [19] results we find that the intrachain nearest neighbour hopping term t ∼ 1.85 eV. Hubbard U, estimated in reference [22], required for a quantitative understanding normal state and high energy properties of Bi is U ∼ 5 to 8 eV. ...
Superconductivity with an ultra low Tc $\sim$ 0.5 mK was discovered recently in bismuth, a semimetal. To develop a model and scenario for Bi we begin with a cubic reference lattice, close to A7 (dimerized cubic) structure of Bi. Three valence electrons hop among 6p$_x$, 6p$_y$ and 6p$_z$ orbitals and form \textit{quasi one dimensional chains at half filling}. An interesting interplay follows: i) Mott localization tendency in the chains, ii) metallization by interchain hopping and iii) lattice dimerization by electron-phonon coupling. In our proposal, a potential high Tc superconductivity from RVB mechanism is lost in the game. However some superconducting fluctuations survive. Tiny fermi pockets seen in Bi are viewed as remnant \textit{evanescent Bogoliubov quasi particles} in an anomalous normal state. Multi band character admits possibility of PT violating \textit{chiral singlet superconductivity}. Bi has a strong spin orbit coupling; Kramers theorem protects our proposal for the bulk by replacing real spin by Kramer pair. Control of chain dimerization might resurrect high Tc superconductivity in Bi, Sb and As.
... The DMFT self-energy, Σ a (ω), requires a solution of the multi-orbital quantum impurity problem self-consistently embedded in an effective medium 36 . We use the multi-orbital iteratedperturbation-theory (MO-IPT) as an impurity solver for DMFT 37 : This analytic solver has a proven record of successes in describing finite temperature Mott transitions 38 as well as unconventional behavior in correlated p-band systems [39][40][41] . ...
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We investigate the physical properties of compressed gray phosphorus through density functional plus dynamical mean-field theory, showing self-doping and s-wave electronic structure reconstruction. At commensurate electron density, the 3p spectrum is shown to be almost unaffected by electronic correlations, however upon self-doping largely the normal and superconducting states. These findings provide a microscopic understanding of pressure-induced hole carrier superconductivity on the normal state coherence of s-wave superconductors with well-defined Bogoliubov quasiparticles at low temperatures. Upon internal thermalization, the s-wave superconducting state loses its phase coherence.
Layered materials with buckled structure offer a promising route to explore distinct phases of quantum matter. Using GGA + DMFT we reveal the complex interplay between perpendicular electric field and site-diagonal disorder in the Dirac liquid electronic state of silicene. The electronic structure we derive is promising in the sense that it leads to results that might explain why out-of-plane electric field plus moderate disorder can generate marginal Dirac valleys consistent with scanning tunneling spectroscopy of silicene on Ag substrates.
Graphic Abstract
Using density-functional dynamical mean-field theory (DFDMFT) we show the importance of multiorbital electronic correlations in determining the insulating state of BiFeO3, a multiferroic material with an electron band gap larger than its bare bandwidth. Within the Fe3+ oxidation state and using realistic values for the on-site Coulomb interaction, we unveil strongly correlated key features probed in x-ray photoelectron and absorption spectra, showing good qualitative theory-experiment agreement. We explore the electronic reconstruction hidden in ferromagnetic BiFeO3, predicting broad orbital- and spin-polarized features at low temperatures. Our proposal for ferromagnetic BiFeO3 is expected to be an important step to understanding the emergent correlated electronic structure of magnetoelectronic and spintronic materials with persisting ordered localized moments coexisting with Coulomb reconstructed electronic states.
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We investigate anisotropic electronic structure and thermal transport properties of bulk black phosphorus (BP). Using density functional dynamical mean-field theory we first derive a correlation-induced electronic reconstruction, showing band-selective Kondoesque physics in this elemental p-band material. The resulting correlated picture is expected to shed light onto the temperature and doping dependent evolution of resistivity, Seebeck coefficient, and thermal conductivity, as seen in experiments on bulk single crystal BP. Therein, large anisotropic particle-hole excitations are key to consistently understand thermoelectric transport responses of pure and doped BP.
