1
|
Tranquada JM, Xu G, Zaliznyak IA. Magnetism and superconductivity in Fe 1+y Te 1-xSe x. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:374003. [PMID: 31412327 DOI: 10.1088/1361-648x/ab3b3b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 08/14/2019] [Indexed: 06/10/2023]
Abstract
Neutron scattering has played a significant role in characterizing magnetic and structural correlations in Fe1+y Te1-xSexand their connections with superconductivity. Here we review several key aspects of the physics of iron chalcogenide superconductors where neutron studies played a key role. These topics include the phase diagram of Fe1+y Te1-xSex, where the doping-dependence of structural transitions can be understood from a mapping to the anisotropic random field Ising model. We then discuss orbital-selective Mott physics in the Fe chalcogenide series, where temperature-dependent magnetism in the parent material provided one of the earliest cases for orbital-selective correlation effects in a Hund's metal. Finally, we elaborate on the character of local magnetic correlations revealed by neutron scattering, its dependence on temperature and composition, and the connections to nematicity and superconductivity.
Collapse
Affiliation(s)
- J M Tranquada
- Brookhaven National Laboratory, Condensed Matter & Materials Science Division, Upton, NY 11973-5000, United States of America
| | - Guangyong Xu
- NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, United States of America
| | - I A Zaliznyak
- Brookhaven National Laboratory, Condensed Matter & Materials Science Division, Upton, NY 11973-5000, United States of America
| |
Collapse
|
2
|
Igoshev PA, Timirgazin MA, Gilmutdinov VF, Arzhnikov AK, Irkhin VY. Spiral magnetism in the single-band Hubbard model: the Hartree-Fock and slave-boson approaches. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:446002. [PMID: 26465091 DOI: 10.1088/0953-8984/27/44/446002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The ground-state magnetic phase diagram is investigated within the single-band Hubbard model for square and different cubic lattices. The results of employing the generalized non-correlated mean-field (Hartree-Fock) approximation and generalized slave-boson approach by Kotliar and Ruckenstein with correlation effects included are compared. We take into account commensurate ferromagnetic, antiferromagnetic, and incommensurate (spiral) magnetic phases, as well as phase separation into magnetic phases of different types, which was often lacking in previous investigations. It is found that the spiral states and especially ferromagnetism are generally strongly suppressed up to non-realistically large Hubbard U by the correlation effects if nesting is absent and van Hove singularities are well away from the paramagnetic phase Fermi level. The magnetic phase separation plays an important role in the formation of magnetic states, the corresponding phase regions being especially wide in the vicinity of half-filling. The details of non-collinear and collinear magnetic ordering for different cubic lattices are discussed.
Collapse
Affiliation(s)
- P A Igoshev
- Institute of Metal Physics, Kovalevskaya str. 18, Ekaterinburg 620990, Russia. Ural Federal University, 620002 Ekaterinburg, Russia
| | | | | | | | | |
Collapse
|
3
|
Spin-liquid polymorphism in a correlated electron system on the threshold of superconductivity. Proc Natl Acad Sci U S A 2015; 112:10316-20. [PMID: 26240327 DOI: 10.1073/pnas.1503559112] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We report neutron scattering measurements which reveal spin-liquid polymorphism in an "11" iron chalcogenide superconductor. It occurs when a poorly metallic magnetic state of FeTe is tuned toward superconductivity by substitution of a small amount of tellurium with isoelectronic sulfur. We observe a liquid-like magnetic response, which is described by the coexistence of two disordered magnetic phases with different local structures whose relative abundance depends on temperature. One is the ferromagnetic (FM) plaquette phase observed in undoped, nonsuperconducting FeTe, which preserves the C4 symmetry of the underlying square lattice and is favored at high temperatures, whereas the other is the antiferromagnetic plaquette phase with broken C4 symmetry, which emerges with doping and is predominant at low temperatures. These findings suggest the coexistence of and competition between two distinct liquid states, and a liquid-liquid phase transformation between these states, in the electronic spin system of FeTe(1-x)(S,Se)(x). We have thus discovered the remarkable physics of competing spin-liquid polymorphs in a correlated electron system approaching superconductivity. Our results facilitate an understanding of large swaths of recent experimental data in unconventional superconductors. In particular, the phase with lower C2 local symmetry, whose emergence precedes superconductivity, naturally accounts for a propensity for forming electronic nematic states which have been observed experimentally, in cuprate and iron-based superconductors alike.
Collapse
|
4
|
Zhao J, Rotundu CR, Marty K, Matsuda M, Zhao Y, Setty C, Bourret-Courchesne E, Hu J, Birgeneau RJ. Effect of electron correlations on magnetic excitations in the isovalently doped iron-based superconductor Ba(Fe(1-x)Ru(x))(2)As(2). PHYSICAL REVIEW LETTERS 2013; 110:147003. [PMID: 25167027 DOI: 10.1103/physrevlett.110.147003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Indexed: 06/03/2023]
Abstract
Magnetic correlations in isovalently doped Ba(Fe(1-x)Ru(x))(2)As(2) (x = 0.25, T(c) = 14.5 K; x = 0.35, T(c) = 20 K) are studied by elastic and inelastic neutron scattering techniques. A relatively large superconducting spin gap accompanied by a weak resonance mode is observed in the superconducting state in both samples. In the normal state, the magnetic excitation intensity is dramatically reduced with increasing Ru doping toward the optimally doped regime. Our results favor that the weakening of the electron-electron correlations by Ru doping is responsible for the dampening of the resonance mode, as well as the suppression of the normal state antiferromagnetic correlations near the optimally doped regime in this system.
Collapse
Affiliation(s)
- Jun Zhao
- Department of Physics, and Laboratory of Advanced Materials, State Key Laboratory of Surface Physics, Fudan University, Shanghai 200433, People's Republic of China and Department of Physics, University of California, Berkeley, California 94720, USA and Miller Institute for Basic Research in Science, Berkeley, California 94720, USA
| | - C R Rotundu
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - K Marty
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - M Matsuda
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Y Zhao
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA and Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA
| | - C Setty
- Department of Physics, Purdue University, West Lafayette, Indiana 47907, USA
| | - E Bourret-Courchesne
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Jiangping Hu
- Department of Physics, Purdue University, West Lafayette, Indiana 47907, USA
| | - R J Birgeneau
- Department of Physics, University of California, Berkeley, California 94720, USA and Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| |
Collapse
|