Robust antiferromagnetism preventing superconductivity in pressurized (Ba0.61K0.39)Mn2Bi2

Gu, Dachun; Dai, Xianying; Le, Congcong; Sun, Liling; Wu, Qi; Saparov, Bayrammurad; Guo, Jing; Gao, Peiwen; Zhang, Shan; Zhou, Yazhou; Zhang, Chao; Jin, Shifeng; Xiong, Lun; Li, Rui; Li, Yanchun; Li, Xiaodong; Liu, Ru; Sefat, Athena S.; Hu, Jiangping; Zhao, Zhongxian

doi:10.1038/srep07342

Cited by 5 publications

(3 citation statements)

References 55 publications

(108 reference statements)

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“…Based on this observation, as e g orbitals are closely involved with the direct NN exchange mechanism, which is expected to be dominant. In fact, this is indeed the case, as shown in BaMn 2 As 2 , and the direct exchange magnetism is very strong in Mn-based compounds, which leads to a G-type AFM state [58], rather than the E-type AFM state in BaFe 2 As 2 .…”

Section: Emergence Of Magnetic Selection Pairing Rule and Fundamentalmentioning

confidence: 81%

Robustness of s-wave pairing symmetry in iron-based superconductors and its implications for fundamentals of magnetically driven high-temperature superconductivity

Yuan

2016

Front. Phys.

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Based on the assumption that the superconducting state belongs to a single irreducible representation of lattice symmetry, we propose that the pairing symmetry in all measured iron-based superconductors is generally consistent with the A 1g s-wave. Robust s-wave pairing throughout the different families of iron-based superconductors at different doping regions signals two fundamental principles behind high-T c superconducting mechanisms: (i) the correspondence principle: the short-range magnetic-exchange interactions and the Fermi surfaces act collaboratively to achieve high-T c superconductivity and determine pairing symmetries; (ii) the magnetic-selection pairing rule: superconductivity is only induced by the magnetic-exchange couplings from the super-exchange mechanism through cation-anion-cation chemical bonding. These principles explain why unconventional high-T c superconductivity appears to be such a rare but robust phenomena, with its strict requirements regarding the electronic environment. The results will help us to identify new electronic structures that can support high-T c superconductivity.

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Section: Emergence Of Magnetic Selection Pairing Rule and Fundamentalmentioning

confidence: 81%

Robustness of s-wave pairing symmetry in iron-based superconductors and its implications for fundamentals of magnetically driven high-temperature superconductivity

Yuan

2016

Front. Phys.

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“…Thus, doping Mn pnictide systems toward metallicity may generically lead to ferromagnetic fluctuations or even order, with limited suppression of the antiferromagnetic order. On the other hand, pressure was found to transform LaMnPO from an antiferromagnetic insulator to an antiferromagnetic metal at 20 GPa and eventually to a paramagnetic metal at 34 GPa [8,35] while 20 GPa did not suppress the long range antiferromagnetic order in Ba 0.61 K 0.39 Mn 2 Bi 2 below 300 K [36]. In both cases, no ferromagnetism was detected and it appears to be the case that only pressure can transform Mn pnictide insulators into potentially correlated Hund's metals, a now familiar breeding ground for superconductivity.…”

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confidence: 95%

From Hund's insulator to Fermi liquid: Optical spectroscopy study of K doping inBaMn2As2

et al. 2015

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We present optical transmission measurements that reveal a charge gap of 0.86 eV in the local moment antiferromagnetic insulator BaMn2As2 , an order of magnitude larger than previously reported. Density functional theory plus dynamical mean field theory (DFT+DMFT) calculations correctly reproduce this charge gap only when a strong Hund's coupling is considered. Thus, BaMn2As2 is a member of a wider class of Mn pnictide compounds that are Mott-Hund's insulators. We also present optical reflectance for metallic 2% K doped BaMn2As2 that we use to extract the optical conductivity at different temperatures. The optical conductivity σ1(ω) exhibits a metallic response that is well described by a simple Drude term. Both σ(ω→0, T) and ρ(T) exhibit Fermi liquid temperature dependencies. From these measurements, we argue that a more strongly correlated Hund's metal version of the parent compounds of the iron pnictide superconductors has not yet been realized by doping this class of Hund's insulators.

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“…As we know, in the cuprates, Fe-pnictides, and heavy-fermion compounds, doping or applying a pressure can suppress the AFM order, then unconventional SC emerges. Here, although we can’t figure out the pressure dependence of T N by using only resistance measurements as discussed above, we suspect that the AFM order in BaMnBi 2 seems impossible to be suppressed by such low pressure (≤2.6 GPa), just like the robust antiferromagnetism under high pressure in (Ba 0.61 K 0.39 )Mn 2 Bi 2 29 , which contains the similar Mn 2 Bi 2 layers. Taken this assumption, then the SC observed here should originate from the electrons in Bi square net, which host both Dirac and parabolic states.…”

Section: Resultsmentioning

confidence: 90%

Pressure induced superconductivity in the antiferromagnetic Dirac material BaMnBi2

Chen

Zhu

et al. 2017

Sci Rep

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The so-called Dirac materials such as graphene and topological insulators are a new class of matter different from conventional metals and (doped) semiconductors. Superconductivity induced by doing or applying pressure in these systems may be unconventional, or host mysterious Majorana fermions. Here, we report a successfully observation of pressure-induced superconductivity in an antiferromagnetic Dirac material BaMnBi2 with T c of ~4 K at 2.6 GPa. Both the higher upper critical field, μ 0 H c2(0) ~ 7 Tesla, and the measured current independent of T c precludes that superconductivity is ascribed to the Bi impurity. The similarity in ρ ab(B) linear behavior at high magnetic fields measured at 2 K both at ambient pressure (non-superconductivity) and 2.6 GPa (superconductivity, but at the normal state), as well as the smooth and similar change of resistivity with pressure measured at 7 K and 300 K in zero field, suggests that there may be no structure transition occurred below 2.6 GPa, and superconductivity observed here may emerge in the same phase with Dirac fermions. Our findings imply that BaMnBi2 may provide another platform for studying SC mechanism in the system with Dirac fermions.

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Robust antiferromagnetism preventing superconductivity in pressurized (Ba0.61K0.39)Mn2Bi2

Cited by 5 publications

References 55 publications

Robustness of s-wave pairing symmetry in iron-based superconductors and its implications for fundamentals of magnetically driven high-temperature superconductivity

Robustness of s-wave pairing symmetry in iron-based superconductors and its implications for fundamentals of magnetically driven high-temperature superconductivity

From Hund's insulator to Fermi liquid: Optical spectroscopy study of K doping inBaMn2As2

Pressure induced superconductivity in the antiferromagnetic Dirac material BaMnBi2

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