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Items from 1 to 20 out of 47 results

article

Thermal quenching of fluorescence in condensed media

Miguel Lagos, Rodrigo Paredes

Solid State Communications > 2016 > 242 > C > 52-56

Environmental factors strongly affect the features of the electromagnetic spectra of fluorescent compounds hosted by material media. The shape of the absorption and emission peaks, their characteristic asymmetry and breadth, the Stokes shift and quantum yield are generally temperature dependent and heavily influenced by both the local and extended physical properties of the medium. The theoretical...

article

First-principles prediction of MgB2-like NaBC: A more promising high-temperature superconducting material than LiBC

Rende Miao, Guiqin Huang, Jun Yang

Solid State Communications > 2016 > 233 > C > 30-34

Crystal structure, lattice dynamics, and superconducting properties for sodium borocarbides NaB_1+xC_1−x are investigated with first-principles calculations. Based on crystal structure analysis by particle swarm optimization methodology, NaBC is predicted to crystallize in the layered P63/mmc crystal structure as LiBC. However, it is different from LiBC, in that Na atoms are effectively ionized, with...

article

Systematics in the metal-insulator transition temperatures in vanadium oxides

B. Fisher, J. Genossar, G.M. Reisner

Solid State Communications > 2016 > 226 > Complete > 29-32

Nine of the known vanadium oxides, VO2−1/n (n – a positive or negative integer) with n=2−6,8,9,∞ and −6, undergo metal-insulator transitions accompanied by structural transitions, at various temperatures T_MIT (V₇O₁₃ is metallic above T=0). Among the persistent efforts to determine the driving force(s) of these transitions, electron–electron (Mott-like) and electron–phonon (Peierls-like) interactions,...

article

Electron–phonon interaction and superconductivity in SnAs with the sodium chloride crystal structure

H.M. Tütüncü, G.P. Srivastava

Solid State Communications > 2015 > 221 > Complete > 24-27

The ground state and electronic properties of the recently discovered superconducting SnAs in the sodium chloride crystal structure have been examined using density functional theory within the generalized gradient approximation. The results indicate that the density of states at the Fermi level is primarily derived from As p states, which strongly hybridize with Sn p states. The phonon dispersion...

article

Lattice dynamics and superconducting properties of antiperovskite La3InZ (Z=N,O)

Swetarekha Ram, V. Kanchana

Solid State Communications > 2014 > 181 > Complete > 54-59

Electronic and superconducting properties of La ₃ InZ (Z=N, O) compounds are studied and are compared with La ₃ In. From the density of states of La ₃ InZ it is quite clear that the hybridization between La-d and In-p states gets reduced with the inclusion of the Z atom in comparison with La ₃ In. A Fermi surface topology change is observed only in La ₃ InO...

article

Phonon states of polar mixing optical modes in wurtzite ZnO-based coupling quantum dots

Li Zhang, J.J. Shi

Solid State Communications > 2014 > 177 > Complete > 68-73

Within the framework of the macroscopic dielectric continuum model and Loudon's uniaxial crystal model, the phonon modes of a wurtzite ZnO-based coupling quantum dots (CQDs) are deduced and studied. The analytical phonon states of phonon modes are given. It is found that there are four types of polar phonon modes, i.e. the z-IO/ρ-QC modes, z-PR/ρ-IO modes, z-QC/ρ-QC modes and z-HS/ρ-IO modes coexisting...

article

First-principles calculation of superconductivity in hole-doped LiBC: Through partial substitution of B or C atoms

Rende Miao, Lei Zhang, Cuicui Liu, Jun Yang, more

Solid State Communications > 2013 > 168 > Complete > 15-18

Electronic structure, lattice dynamics, and superconducting properties for hypothetical LiB _0.9 Be _0.1 C are obtained by first-principles calculations within the virtual-crystal approximation treatment. The electronic structure for LiB _0.9 Be _0.1 C is cross checked using supercell method. We show that hole doping of LiBC through partial substitution of B by Be atoms...

article

Exact distribution function of a one-dimensional Fro¨hlich–Toyozawa–Luttinger liquid

P.J. Monisha, Soma Mukhopadhyay, Ashok Chatterjee

Solid State Communications > 2013 > 166 > Complete > 83-86

An exact analytical expression for the electron momentum distribution function of a one-dimensional Frohlich–Toyozawa–Luttinger (FTL) liquid is obtained. It is explicitly shown that the residual Fermi surface disappears when the electron–electron interaction is increased. It is furthermore shown that the electron–phonon interactions also flatten the distribution function, the optical phonons having...

article

Origin of the temperature dependence of the band gap of PbS and PbSe quantum dots

P. Dey, J. Paul, J. Bylsma, D. Karaiskaj, more

Solid State Communications > 2013 > 165 > Complete > 49-54

The lead chalcogenides semiconductor materials show in the bulk a shift of the electronic band gap with temperature that is opposite to the majority of direct or indirect band gap semiconductors, namely they show a decreasing of the band gap energy with decreasing temperature. However, in the nanocrystalline form a peculiar behavior has been observed. The shift of the band gap energy with temperature...

article

First-principles study on iron-pnictide superconductors Ca(Fe1−xCox)2As2

Rende Miao, Zhong Bai, Jun Yang, Xuan Chen, more

Solid State Communications > 2013 > 154 > Complete > 11-14

The electronic structure, lattice dynamics, and electron–phonon (e–ph) coupling constants λ for the superconducting Ca(Fe _1−x Co _x ) ₂ As ₂ (x=0.075, 0.1) are obtained by first-principles nonmagnetic calculations using norm-conserving pseudopotentials within virtual–crystal approximation treatment. Combined with the e–ph coupling constant λ for vicinity of collapsed...

article

Chemical trend of superconducting transition temperature in hole-doped delafossite of CuAlO2, AgAlO2 and AuAlO2

Akitaka Nakanishi, Hiroshi Katayama-Yoshida

Solid State Communications > 2012 > 152 > 23 > 2078-2081

We have performed the first-principles calculations about the superconducting transition temperature Tc of hole-doped delafossite CuAlO ₂ , AgAlO ₂ and AuAlO ₂ . Calculated Tc are about 50K (CuAlO ₂ ), 40K (AgAlO ₂ ) and 3K(AuAlO ₂ ) at maximum in the optimum hole-doping concentration. The low Tc of AuAlO ₂ is attributed to the weak electron–phonon...

article

One and two-phonon processes of the spin–flip relaxation in quantum dots: Spin–phonon coupling mechanism

Zi-Wu Wang, Shu-Shen Li

Solid State Communications > 2012 > 152 > 13 > 1098-1102

We investigate the spin–flip relaxation in quantum dots using a non-radiation transition approach based on the descriptions for the electron–phonon deformation potential and Fröhlich interaction in the Pavlov–Firsov spin–phonon Hamiltonian. We give the comparisons of the electron relaxations with and without spin–flip assisted by one and two-phonon processes. Calculations are performed for the dependence...

article

Structural transition, ferro-orbital order and its fluctuation-mediated s++-wave superconductivity in iron pnictides

Yoshiaki Ōno, Yuki Yanagi, Naoko Adachi, Youichi Yamakawa

Solid State Communications > 2012 > 152 > 8 > 701-710

We investigate the electronic states and the superconductivity in the two-dimensional 16-band d–p model extracted from a tight-binding fit to the band structure of iron pnictides, in the presence of both the Coulomb interaction between Fe d-electrons and the electron–lattice coupling g with the orthorhombic mode which is crucial for reproducing the recently observed ultrasonic softening of the elastic...

article

First-principles study on the lattice dynamics of FeSb2

Rende Miao, Guiqin Huang, Chunhui Fan, Zhong Bai, more

Solid State Communications > 2012 > 152 > 3 > 231-234

The lattice dynamics of FeSb ₂ are investigated by first-principles calculations based on a plane wave pseudopotential method. Phonon spectrum and the electron–phonon linewidths at the Γ-point are obtained using the density-functional perturbation theory within the linear response method. Nine phonon modes are in good agreement with the experimental data, but the B3g mode shows unusually large...

article

Computational materials design for superconductivity in hole-doped delafossite CuAlO2 : Transparent superconductors

Akitaka Nakanishi, Hiroshi Katayama-Yoshida

Solid State Communications > 2012 > 152 > 1 > 24-27

We have calculated the superconducting critical temperature Tc of hole-doped delafossite CuAlO ₂ based on first-principles calculations. According our calculation, 0.2–0.3 hole-doped CuAlO ₂ can become a phonon-mediated high-Tc superconductor with Tc≃50K. In the hole-doped CuAlO ₂ , the A ₁ L ₁ phonon mode that stretches the O–Cu–O dumbbell has a strong interaction...

article

Spin–flip relaxation in a two-electron quantum dot with spin–phonon coupling

Zi-Wu Wang, Shu-Shen Li

Solid State Communications > 2011 > 151 > 22 > 1667-1671

We study the spin–flip process from the first excited state to the ground state due to the spin–phonon coupling in a two-electron quantum dot in the presence of a magnetic field. We give several possible relaxation channels before and after the crossing of the Zeeman sublevels. Our results show that the Coulomb interactions between the electrons of different channels play quite different roles and...

article

Manifestation of LO–LA phonons in Raman scattering in graphene

Raffaello Ferone, John R. Wallbank, Viktor Zólyomi, Edward McCann, more

Solid State Communications > 2011 > 151 > 16 > 1071-1074

We analyze the spectral density of Raman scattering in graphene accompanied by the emission of a pair of LO or LA phonons from the corner of the Brillouin zone. Using a minimal tight-binding model approach, we find that the lineshape of the corresponding Raman signal consists of two peaks with a strongly non-Lorentzian (almost triangular) form with their width and the splitting between the peaks being...

article

Feynman’s path-integral polaron treatment approached using time-ordered operator calculus

S.N. Klimin, J.T. Devreese

Solid State Communications > 2011 > 151 > 2 > 144-147

The Feynman all-coupling variational approach for the polaron is re-formulated and extended using the Hamiltonian formalism with time-ordered operator calculus. Special attention is devoted to the excited polaron states. The energy levels and the inverse lifetimes of the excited polaron states are, for the first time, explicitly derived within this all-coupling approach. Remarkable agreement of the...

article

CaSi2, the antibonding-sister of MgB2?

C. Loison, H. Rosner

Solid State Communications > 2010 > 150 > 41-42 > 2076-2079

The crystalline and electronic structures of CaSi ₂ under high-pressure are very similar to those of MgB ₂ . As CaSi ₂ has two more valence electrons than MgB ₂ , the highest occupied σ band is bonding for MgB ₂ and antibonding in CaSi ₂ . We investigated whether high-pressure CaSi ₂ superconductivity is similar to that in MgB ₂ , with...

article

Phonon-assisted energy up-conversion process of Er3+ ions doped in KY F4 crystal

Ta-Ryeong Park

Solid State Communications > 2010 > 150 > 29-30 > 1378-1381

Er ³⁺ ions doped in KY F ₄ crystal emit blue photoluminescence around 406 nm by energy up-conversion process when excited by 532 or 488 nm laser. By measuring the temperature dependence of up-converted luminescence, we found that the up-conversion process is enhanced with increasing temperature, which is an indication that phonons are assisting the process. This observation is supported...

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Keywords

D. ELECTRON–PHONON INTERACTIONS (47)
A. SUPERCONDUCTORS (10)
A. SEMICONDUCTORS (9)
D. PHONONS (9)
D. OPTICAL PROPERTIES (5)
A. GRAPHENE (3)
A. HIGH-TC SUPERCONDUCTORS (3)
A. THIN FILMS (3)
D. ELECTRONIC BAND STRUCTURE (3)
D. ELECTRONIC TRANSPORT (3)
D. PHASE TRANSITIONS (3)
E. LUMINESCENCE (3)
E. RAMAN SPECTROSCOPY (3)
A. NANOSTRUCTURES (2)
C. CRYSTAL STRUCTURE AND SYMMETRY (2)
C. DELAFOSSITE STRUCTURE (2)
C. ELECTRONIC BAND STRUCTURE (2)
D. ELECTRON–ELECTRON INTERACTIONS (2)
D. EXCHANGE AND SUPEREXCHANGE (2)
D. OPTICAL PHONON MODES (2)
D. SPIN DYNAMICS (2)
E. DENSITY FUNCTIONAL THEORY (2)
E. FIRST-PRINCIPLES (2)
E. LIGHT ABSORPTION AND REFLECTION (2)
74.25GZ (1)
74.72-H (1)
A. CARBON (1)
A. DISORDERED SYSTEMS (1)
A. FESB2 (1)
A. GRANULAR FILMS (1)
A. INSULATORS (1)
A. IRON PNICTIDES (1)
A. MANGANITES (1)
A. METAL-SEMICONDUCTOR (1)
A. METALS (1)
A. SEMICONDUCTOR (1)
A. SUPERCONDUCTOR (1)
A. WURTZITE CYLINDRICAL QUANTUM DOTS (1)
A. WURTZITE MULTI-SHELL HETEROSTRUCTURES (1)
A. WURTZITE ZNO-BASED SEMICONDUCTOR (1)
B. DENSITY FUNCTIONAL THEORY (1)
B. ELECTRONIC BAND STRUCTURE (1)
B. NANOSTRUCTURES (1)
C. COUPLING QUANTUM DOTS (1)
D. ELASTICITY (1)
D. ELECTRON GREEN FUNCTION (1)
D. ELECTRONIC STATES (LOCALIZED) (1)
D. ELECTRONIC STRUCTURE (1)
D. LUTTINGER LIQUID (1)
D. MAGNETIC SUSCEPTIBILITY (1)
D. MOMENTUM DISTRIBUTION (1)
D. OPTICAL SUM RULES (1)
D. ORDER–DISORDER EFFECTS (1)
D. PHONON (1)
D. PHONON MODE (1)
D. POLAR OPTICAL PHONON MODES (1)
D. POLARONS (1)
E. ELECTRON PARAMAGNETIC RESONANCE (1)
E. FIRST-PRINCIPLES. (1)
E. INELASTIC LIGHT SCATTERING (1)
E. LUMINISCENCE (1)
E. NEUTRON SCATTERING (1)
E. PHOTOELECTRON SPECTROSCOPIES (1)
E. TIME-RESOLVED OPTICAL (1)
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INFONA - science communication portal

Search results

Thermal quenching of fluorescence in condensed media

First-principles prediction of MgB2-like NaBC: A more promising high-temperature superconducting material than LiBC

Systematics in the metal-insulator transition temperatures in vanadium oxides

Electron–phonon interaction and superconductivity in SnAs with the sodium chloride crystal structure

Lattice dynamics and superconducting properties of antiperovskite La3InZ (Z=N,O)

Phonon states of polar mixing optical modes in wurtzite ZnO-based coupling quantum dots

First-principles calculation of superconductivity in hole-doped LiBC: Through partial substitution of B or C atoms

Exact distribution function of a one-dimensional Fro¨hlich–Toyozawa–Luttinger liquid

Origin of the temperature dependence of the band gap of PbS and PbSe quantum dots

First-principles study on iron-pnictide superconductors Ca(Fe1−xCox)2As2

Chemical trend of superconducting transition temperature in hole-doped delafossite of CuAlO2, AgAlO2 and AuAlO2

One and two-phonon processes of the spin–flip relaxation in quantum dots: Spin–phonon coupling mechanism

Structural transition, ferro-orbital order and its fluctuation-mediated s++-wave superconductivity in iron pnictides

First-principles study on the lattice dynamics of FeSb2

Computational materials design for superconductivity in hole-doped delafossite CuAlO2 : Transparent superconductors

Spin–flip relaxation in a two-electron quantum dot with spin–phonon coupling

Manifestation of LO–LA phonons in Raman scattering in graphene

Feynman’s path-integral polaron treatment approached using time-ordered operator calculus

CaSi2, the antibonding-sister of MgB2?

Phonon-assisted energy up-conversion process of Er3+ ions doped in KY F4 crystal

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