Pressure Induced Superconductivity in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>CaFe</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>As</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math>

Torikachvili, M. S.; Bud’ko, Sergey L.; Ni, Ni; Canfield, Paul C.

doi:10.1103/physrevlett.101.057006

Cited by 615 publications

(717 citation statements)

References 6 publications

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“…Similar as in LaFeAsO [7,8], these ternary iron arsenides also exhibit a spin-density-wave-like anomaly and a structural transition from the tetragonal I4/mmm to the orthorhombic F mmm group at some temperature between 140 K and 200 K [9,10]. Furthermore, it was found that the high pressures can drive these undoped ternary iron arsenides superconducting [11][12][13].…”

Section: Introductionmentioning

confidence: 95%

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Electronic structures of ternary iron arsenides AFe2As2 (A = Ba, Ca, or Sr)

Lu²,

Xiang³

2009

Front. Phys. China

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We have studied the electronic and magnetic structures of the ternary iron arsenides AFe 2 As 2 (A = Ba, Ca, or Sr) using the first-principles density functional theory. The ground states of these compounds are in a collinear antiferromagnetic order, resulting from the interplay between the nearest and the next-nearest neighbor superexchange antiferromagnetic interactions bridged by As 4p orbitals. The correction from the spin-orbit interaction to the electronic band structure is given. The pressure can reduce dramatically the magnetic moment and diminish the collinear antiferromagnetic order. Based on the calculations, we propose that the low energy dynamics of these materials is described effectively by a t − J H − J 1 − J 2 -type model [1].

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Section: Introductionmentioning

confidence: 95%

“…Experimentally it was reported [11][12][13] that the ternary iron arsenides AFe 2 As 2 (A=Ba, Ca, or Sr) can become superconducting under high pressures without doping. This provides another route to study the salient features of these materials in connection with the intrinsic electronic structures and properties.…”

Section: E Pressure Effectmentioning

confidence: 99%

Electronic structures of ternary iron arsenides AFe2As2 (A = Ba, Ca, or Sr)

Lu²,

Xiang³

2009

Front. Phys. China

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“…The application of modest pressure (a few kbars) was found to cause CaFe 2 As 2 to go superconducting [34]. Pressure dependent neutron diffraction measurements revealed a dramatic change in the crystal structure-a strongly first-order phase transition to a "collapsed" tetragonal phase [25,26].…”

Section: Cafe 2 As 2 Under Pressurementioning

confidence: 99%

Neutron studies of the iron-based family of high TC magnetic superconductors

Lynn

Dai

2009

Physica C: Superconductivity

154

163

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We review neutron scattering investigations of the crystal structures, magnetic structures, and spin dynamics of the iron-based RFe(As,P)O (R=La, Ce, Pr, Nd), (Ba,Sr,Ca)Fe 2 As 2 , and Fe 1+x (Te-Se) systems. On cooling from room temperature all the undoped materials exhibit universal behavior, where a tetragonal-to-orthorhombic/monoclinic structural transition occurs, below which the systems become antiferromagnets. For the first two classes of materials the magnetic structure within the a-b plane consists of chains of parallel Fe spins that are coupled antiferromagnetically in the orthogonal direction, with an ordered moment typically less than one Bohr magneton. Hence these are itinerant electron magnets, with a spin structure that is consistent with Fermi-surface nesting and a very energetic spin wave bandwidth ~0.2 eV. With doping, the structural and magnetic transitions are suppressed in favor of superconductivity, with superconducting transition temperatures up to ≈55 K. Magnetic correlations are observed in the superconducting regime, with a magnetic resonance that follows the superconducting order parameter just like the cuprates. The rare-earth moments order antiferromagnetically at low T like 'conventional' magnetic-superconductors, while the Ce crystal field linewidths are affected when superconductivity sets in. The application of pressure in CaFe 2 As 2 transforms the system from a magnetically ordered orthorhombic material to a 'collapsed' non-magnetic tetragonal system. Tetragonal Fe 1+x Te transforms to a low T monoclinic structure at small x that changes to orthorhombic at larger x, which is accompanied by a crossover from commensurate to incommensurate magnetic order.Se doping suppresses the magnetic order, while incommensurate magnetic correlations are observed in the superconducting regime.

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“…By replacing La with other rare earths, T c can be raised to above 50 K [2][3][4][5][6][7]. Late on, the oxygen-free iron arsenide compounds AFe 2 As 2 (denoted as FeAs-122) were discovered and superconductivity was found by appropriate substitution or under pressure [8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Superconductivity induced by doping Ru in SrFe2−xRuxAs2

Wang

Gao

et al. 2009

Physica C: Superconductivity

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Abstract:Using one-step solid state reaction method, we have successfully synthesized the superconductor SrFe 1-x Ru x As. X-ray diffraction indicates that the material has formed the ThCr 2 Si 2 -type structure with a space group I4/mmm. The systematic evolution of the lattice constants demonstrates that the Fe ions are successfully replaced by the Ru.By increasing the doping content of Ru, the spin-density-wave (SDW) transition in the parent compound is suppressed and superconductivity emerges. The maximum superconducting transition temperature is found at 13.5 K with the doping level of x = 0.7. The temperature dependence of DC magnetization confirms superconducting transitions at around 12 K. Our results indicate that similar to non-isoelectronic substitution, isoelectronic substitution contributes to changes in both the carrier concentration and internal pressure, and superconductivity could be induced by isoelectronic substitution.

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Pressure Induced Superconductivity inCaFe2As2

Cited by 615 publications

References 6 publications

Electronic structures of ternary iron arsenides AFe2As2 (A = Ba, Ca, or Sr)

Electronic structures of ternary iron arsenides AFe2As2 (A = Ba, Ca, or Sr)

Neutron studies of the iron-based family of high TC magnetic superconductors

Superconductivity induced by doping Ru in SrFe2−xRuxAs2

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