Electron-phonon superconductivity in LaNiPO

Subedi, Alaska; Singh, David J.; Du, Mao‐Hua

doi:10.1103/physrevb.78.060506

Cited by 422 publications

(732 citation statements)

References 24 publications

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“…It should be noted that, depletion of these states from the near E F clearly indicates an opening up of a pseudogap as the temperature is lowered from 300 K to 77 K. Figure 2(a) shows the calculated total density of states (DOS) over the valence band region. The calculated DOS matches with the earlier theoretical study [21,22] and also with the observed experimental data. Fig 2) corresponds to the experimentally obtained features at 0.1 eV and 0.5 eV, respectively.…”

Section: Resultssupporting

confidence: 88%

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Photoemission studies of the near E_Fspectral weight shifts in FeSe_1−xTe_xsuperconductor

Mishra¹,

Lohani²,

Zargar³

et al. 2014

J. Phys.: Condens. Matter

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Abstract. Our valence band photoelectron spectroscopic studies show a temperature dependent spectral weight transfer near the Fermi level in the Fe-based superconductor FeSe 1−x Te x . Using theoretical band structure calculations we have shown that the weight transfer is due to the temperature induced changes in the Fe(Se,Te) 4 tetrahedra. These structural changes lead to shifts in the electron occupancy from the xz/yz and x 2 -y 2 orbitals to the 3z 2 -r 2 orbitals indicating a temperature induced crossover from a metallic state to an Orbital Selective Mott (OSM) Phase. Our study presents the observation of a temperature induced crossover to a low temperature OSM phase in the family of Fe chalcogenides.

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Section: Resultssupporting

confidence: 88%

“…Peak C at 4 eV is due to the hybridized Fe 3d -Se 4p/Te 5p states while D at 6 eV corresponds to Se 4p/Te 5p states. Our calculations based on the TBLMTO-ASA (fig 2(a)) and also other's calculations [21,22] conform to these assignments. The sharp feature A seen in the case of FeSe transforms into a broadened one for FeTe.…”

Section: Resultssupporting

confidence: 85%

Photoemission studies of the near E_Fspectral weight shifts in FeSe_1−xTe_xsuperconductor

Mishra¹,

Lohani²,

Zargar³

et al. 2014

J. Phys.: Condens. Matter

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“…Interestingly, a (π, π) nested vector is also consistent with the magnetic striping along [110] direction. 14,46 The addition of excess Fe using a rigid band approximation changes the Table 3 for further details concerning (c) and (d). topology of the Fermi surface, particularly at the Γ point.…”

Section: Magnetic Orderingmentioning

confidence: 99%

“…The two former structures contain well separated chalcogenide valence p and metal 3d states, whereas the latter shows a poorly defined pseudogap with the Te 5p bands moving into the same energy range as the Fe 3d states. 14 Fermi surfaces and phonon dispersion curves were also investigated without accounting for spin polarization. Welz and Rosenberg investigated the electronic structure of stoichiometric tetragonal "FeS" and showed the density of states (DOS) does not follow the Stoner criterion for ferromagnetism.…”

Section: Introductionmentioning

confidence: 99%

Validation of Interstitial Iron and Consequences of Nonstoichiometry in Mackinawite (Fe_1+xS)

Brgoch

Miller

2012

J. Phys. Chem. A

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A theoretical investigation of the relationship between chemical composition and electronic structure was performed on the nonstoichiometric iron sulfide, mackinawite (Fe 1+x S), which is isostructural and isoelectronic with the superconducting Fe 1+x Se and Fe 1+x (Te 1-y Se y ) phases. Even though Fe 1+x S has not been measured for superconductivity, the effects of stoichiometry on transport properties and electronic structure in all of these iron-excess chalcogenide compounds has been largely overlooked. In mackinawite, the amount of Fe that has been reported ranges from a large excess, Fe 1.15 S, to nearly stoichiometric, Fe 1.00 (7) S. Here, we analyze, for the first time, the electronic structure of Fe 1+x S to justify these nonstoichiometric phases. First principles electronic structure calculations using supercells of Fe 1+x S yield a wide range of energetically favorable compositions (0 < x < 0.30). The incorporation of interstitial Fe atoms originates from a delicate balance between the Madelung energy and the occupation of Fe-S and Fe-Fe antibonding orbitals. A theoretical assessment of various magnetic structures for "FeS" and Fe 1.06 S indicate that striped magnetic ordering along [110] is the lowest energy structure and the interstitial Fe affects the values of moments in the square planes as a function of distance. Moreover, the formation of the magnetic moment is dependent on the unit cell volume, thus relating it to composition. Finally, changes in the composition cause a modification of the Fermi surface and ultimately the loss of a nested vector. ABSTRACT: A theoretical investigation of the relationship between chemical composition and electronic structure was performed on the nonstoichiometric iron sulfide, mackinawite (Fe 1+x S), which is isostructural and isoelectronic with the superconducting Fe 1+x Se and Fe 1+x (Te 1−y Se y ) phases. Even though Fe 1+x S has not been measured for superconductivity, the effects of stoichiometry on transport properties and electronic structure in all of these iron-excess chalcogenide compounds has been largely overlooked. In mackinawite, the amount of Fe that has been reported ranges from a large excess, Fe 1.15 S, to nearly stoichiometric, Fe 1.00 (7) S. Here, we analyze, for the first time, the electronic structure of Fe 1+x S to justify these nonstoichiometric phases. First principles electronic structure calculations using supercells of Fe 1+x S yield a wide range of energetically favorable compositions (0 < x < 0.30). The incorporation of interstitial Fe atoms originates from a delicate balance between the Madelung energy and the occupation of Fe−S and Fe−Fe antibonding orbitals. A theoretical assessment of various magnetic structures for "FeS" and Fe 1.06 S indicate that striped magnetic ordering along [110] is the lowest energy structure and the interstitial Fe affects the values of moments in the square planes as a function of distance. Moreover, the formation of the magnetic moment is dependent on the unit cell volume, thus relating it to...

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“…where more than one determinant is needed for a qualitative description of the system. Such situations arise in bond breaking [1], large π-conjugated molecules where the HOMO-LUMO gap is small [3], transition metal complexes [4] and superconductivity [5]. For such cases, a single Slater determinant gives qualitatively incorrect results.…”

Section: Introductionmentioning

confidence: 99%

Amplitude Determinant Coupled Cluster with Pairwise Doubles

Zhao

Neuscamman

2016

J. Chem. Theory Comput.

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Recently developed pair coupled cluster doubles (pCCD) theory successfully reproduces doubly occupied configuration interaction (DOCI) with mean field cost. However, the projective nature of pCCD makes the method non-variational and thus hard to improve systematically. As a variational alternative, we explore the idea of coupled-cluster-like expansions based on amplitude determinants and develop a specific theory similar to pCCD based on determinants of pairwise doubles. The new ansatz admits a variational treatment through Monte Carlo methods while remaining size-consistent and, crucially, polynomial cost. In the dissociations of LiH, HF, H2O and N2, the method performs very similarly to pCCD and DOCI, suggesting that coupled-cluster-like ansatzes and variational evaluation may not be mutually exclusive.

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Electron-phonon superconductivity in LaNiPO

Cited by 422 publications

References 24 publications

Photoemission studies of the near E_Fspectral weight shifts in FeSe_1−xTe_xsuperconductor

Photoemission studies of the near E_Fspectral weight shifts in FeSe_1−xTe_xsuperconductor

Validation of Interstitial Iron and Consequences of Nonstoichiometry in Mackinawite (Fe_1+xS)

Amplitude Determinant Coupled Cluster with Pairwise Doubles

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Electron-phonon superconductivity in LaNiPO

Cited by 422 publications

References 24 publications

Photoemission studies of the near EFspectral weight shifts in FeSe1−xTexsuperconductor

Photoemission studies of the near EFspectral weight shifts in FeSe1−xTexsuperconductor

Validation of Interstitial Iron and Consequences of Nonstoichiometry in Mackinawite (Fe1+xS)

Amplitude Determinant Coupled Cluster with Pairwise Doubles

Contact Info

Product

Resources

About

Photoemission studies of the near E_Fspectral weight shifts in FeSe_1−xTe_xsuperconductor

Photoemission studies of the near E_Fspectral weight shifts in FeSe_1−xTe_xsuperconductor

Validation of Interstitial Iron and Consequences of Nonstoichiometry in Mackinawite (Fe_1+xS)