Evidence of strong correlations and coherence-incoherence crossover in the iron pnictide superconductor KFe2As2

F. Hardy, A. E. Böhmer, D. Aoki, P. Burger, T. Wolf, P. Schweiss, R. Heid, P. Adelmann, Y. X. Yao, B Kotliar, J. Schmalian, C. Meingast

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Abstract

Using resistivity, heat-capacity, thermal-expansion, and susceptibility measurements we study the normal-state behavior of KFe2As 2. Both the Sommerfeld coefficient (γ≈103 mJ mol -1 K-2) and the Pauli susceptibility (χ≈4× 10-4) are strongly enhanced, which confirm the existence of heavy quasiparticles inferred from previous de Haas-van Alphen and angle-resolved photoemission spectroscopy experiments. We discuss this large enhancement using a Gutzwiller slave-boson mean-field calculation, which shows the proximity of KFe2As2 to an orbital-selective Mott transition. The temperature dependence of the magnetic susceptibility and the thermal expansion provide strong experimental evidence for the existence of a coherence- incoherence crossover, similar to what is found in heavy fermion and ruthenate compounds, due to Hund's coupling between orbitals.

Original languageEnglish (US)
Article number027002
JournalPhysical review letters
Volume111
Issue number2
DOIs
StatePublished - Jul 9 2013

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incoherence
Group 5A compounds
crossovers
magnetic permeability
iron
thermal expansion
orbitals
proximity
photoelectric emission
bosons
fermions
specific heat
temperature dependence
electrical resistivity
augmentation
coefficients
spectroscopy

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Cite this

Hardy, F., Böhmer, A. E., Aoki, D., Burger, P., Wolf, T., Schweiss, P., ... Meingast, C. (2013). Evidence of strong correlations and coherence-incoherence crossover in the iron pnictide superconductor KFe2As2. Physical review letters, 111(2), [027002]. https://doi.org/10.1103/PhysRevLett.111.027002
Hardy, F. ; Böhmer, A. E. ; Aoki, D. ; Burger, P. ; Wolf, T. ; Schweiss, P. ; Heid, R. ; Adelmann, P. ; Yao, Y. X. ; Kotliar, B ; Schmalian, J. ; Meingast, C. / Evidence of strong correlations and coherence-incoherence crossover in the iron pnictide superconductor KFe2As2. In: Physical review letters. 2013 ; Vol. 111, No. 2.
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abstract = "Using resistivity, heat-capacity, thermal-expansion, and susceptibility measurements we study the normal-state behavior of KFe2As 2. Both the Sommerfeld coefficient (γ≈103 mJ mol -1 K-2) and the Pauli susceptibility (χ≈4× 10-4) are strongly enhanced, which confirm the existence of heavy quasiparticles inferred from previous de Haas-van Alphen and angle-resolved photoemission spectroscopy experiments. We discuss this large enhancement using a Gutzwiller slave-boson mean-field calculation, which shows the proximity of KFe2As2 to an orbital-selective Mott transition. The temperature dependence of the magnetic susceptibility and the thermal expansion provide strong experimental evidence for the existence of a coherence- incoherence crossover, similar to what is found in heavy fermion and ruthenate compounds, due to Hund's coupling between orbitals.",
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Hardy, F, Böhmer, AE, Aoki, D, Burger, P, Wolf, T, Schweiss, P, Heid, R, Adelmann, P, Yao, YX, Kotliar, B, Schmalian, J & Meingast, C 2013, 'Evidence of strong correlations and coherence-incoherence crossover in the iron pnictide superconductor KFe2As2', Physical review letters, vol. 111, no. 2, 027002. https://doi.org/10.1103/PhysRevLett.111.027002

Evidence of strong correlations and coherence-incoherence crossover in the iron pnictide superconductor KFe2As2. / Hardy, F.; Böhmer, A. E.; Aoki, D.; Burger, P.; Wolf, T.; Schweiss, P.; Heid, R.; Adelmann, P.; Yao, Y. X.; Kotliar, B; Schmalian, J.; Meingast, C.

In: Physical review letters, Vol. 111, No. 2, 027002, 09.07.2013.

Research output: Contribution to journalArticle

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T1 - Evidence of strong correlations and coherence-incoherence crossover in the iron pnictide superconductor KFe2As2

AU - Hardy, F.

AU - Böhmer, A. E.

AU - Aoki, D.

AU - Burger, P.

AU - Wolf, T.

AU - Schweiss, P.

AU - Heid, R.

AU - Adelmann, P.

AU - Yao, Y. X.

AU - Kotliar, B

AU - Schmalian, J.

AU - Meingast, C.

PY - 2013/7/9

Y1 - 2013/7/9

N2 - Using resistivity, heat-capacity, thermal-expansion, and susceptibility measurements we study the normal-state behavior of KFe2As 2. Both the Sommerfeld coefficient (γ≈103 mJ mol -1 K-2) and the Pauli susceptibility (χ≈4× 10-4) are strongly enhanced, which confirm the existence of heavy quasiparticles inferred from previous de Haas-van Alphen and angle-resolved photoemission spectroscopy experiments. We discuss this large enhancement using a Gutzwiller slave-boson mean-field calculation, which shows the proximity of KFe2As2 to an orbital-selective Mott transition. The temperature dependence of the magnetic susceptibility and the thermal expansion provide strong experimental evidence for the existence of a coherence- incoherence crossover, similar to what is found in heavy fermion and ruthenate compounds, due to Hund's coupling between orbitals.

AB - Using resistivity, heat-capacity, thermal-expansion, and susceptibility measurements we study the normal-state behavior of KFe2As 2. Both the Sommerfeld coefficient (γ≈103 mJ mol -1 K-2) and the Pauli susceptibility (χ≈4× 10-4) are strongly enhanced, which confirm the existence of heavy quasiparticles inferred from previous de Haas-van Alphen and angle-resolved photoemission spectroscopy experiments. We discuss this large enhancement using a Gutzwiller slave-boson mean-field calculation, which shows the proximity of KFe2As2 to an orbital-selective Mott transition. The temperature dependence of the magnetic susceptibility and the thermal expansion provide strong experimental evidence for the existence of a coherence- incoherence crossover, similar to what is found in heavy fermion and ruthenate compounds, due to Hund's coupling between orbitals.

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