ARPES studies of the inverse perovskite 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Ca</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:mi>PbO</mml:mi></mml:mrow></mml:math>
: Experimental confirmation of a candidate 3D Dirac fermion system

Obata, Yukiko; Yukawa, Ryu; Horiba, Koji; Kumigashira, Hiroshi; Yoshitake, T.; Matsuishi, Satoru; Hosono, Hideo

doi:10.1103/physrevb.96.155109

Cited by 42 publications

(26 citation statements)

References 63 publications

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“…This good agreement confirms the scenario that minute spontaneous Sr deficiency leads to a minor absorption with relatively strong intensity. Similar amount of the Ca deficiency is reported by EPMA in a single crystal of Ca 3 PbO [9]. Such amount of deficiency should be insufficient to trigger superconductivity.…”

Section: A Sample Characterizationsupporting

confidence: 74%

“…This result supports that the actual x value of the NS sample is indeed small, but also suggests that there is a certain amount of the spontaneous Sr deficiency even in the NS sample. We note that Ca deficiency and corresponding hole doping are observed in a single crystal of Ca 3 PbO by the electron-probe microanalysis (EPMA) and ARPES [9]. For the samples prepared with the similar conditions to the D sample, EDX shows a substantial spatial distribution of the Sr/Sn ratio, with the largest population at Sr/Sn = 2.5 (i.e.…”

Section: A Sample Preparationmentioning

confidence: 83%

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Negative ionic states of tin in the oxide superconductor Sr3−xSnO revealed by Mössbauer spectroscopy

et al. 2019

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We report the temperature variation of the 119 Sn-Mössbauer spectra of the antiperovskite (inverse perovskite) oxide superconductor Sr3-x SnO. Both superconductive (Sr-deficient) and nonsuperconductive (nearly stoichiometric) samples exhibit major γ-ray absorption with isomer shift similar to that of Mg2Sn. This fact shows that Sr3-x SnO contains the metallic anion Sn 4 -, which is rare especially among oxides. In both samples, we observed another γ-ray absorption with a larger isomer shift, indicating that there is another ionic state of Sn with a higher oxidation number. The temperature dependence of the absorption intensities reveals that the Sn ions exhibiting larger isomer shifts have a lower energy of the local vibration. The larger isomer shift and lower vibration energy are consistent with the values estimated from the first-principles calculations for hypothetical structures with various Sr-deficiency arrangements. Therefore, we conclude that the additional γ-ray absorptions originate from the Sn atoms neighboring the Sr deficiency. :1911.12934v1 [cond-mat.mtrl-sci] arXiv

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Section: A Sample Characterizationsupporting

confidence: 74%

Section: A Sample Preparationmentioning

confidence: 83%

Negative ionic states of tin in the oxide superconductor Sr3−xSnO revealed by Mössbauer spectroscopy

et al. 2019

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“…The predicted Dirac dispersion has been experimentally observed in single-crystalline Ca 3 PbO through soft x-ray angle-resolved photoemission spectroscopy [8]. Moreover, semiconducting behavior and room-temperature ferromagnetism were observed in thin films of nearly stoichiometric * kitagawa.shunsaku.8u@kyoto-u.ac.jp Sr 3−x SnO (x ∼ 0) [9][10][11].…”

mentioning

confidence: 81%

Normal-state properties of the antiperovskite oxide Sr3−xSnO revealed by Sn119 -NMR

Kitagawa¹,

Ishida²,

Oudah³

et al. 2018

Phys. Rev. B

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We have performed 119 Sn-NMR measurements on the antiperovskite oxide superconductor Sr 3−x SnO to investigate how its normal state changes with the Sr deficiency. A two-peak structure was observed in the NMR spectra of all the measured samples. This suggests that the phase separation tends to occur between the nearly stoichiometric and heavily Sr-deficient Sr 3−x SnO phases. The measurement of the nuclear spin-lattice relaxation rate 1/T 1 indicates that the Sr-deficient phase shows a conventional metallic behavior due to the heavy hole doping. In contrast, the nearly stoichiometric phase exhibits unusual temperature dependence of 1/T 1 , attributable to the presence of a Dirac-electron band.

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“…However, the actual band gap, which lies along the Γ-X line at six equivalent points in the Brillouin zone (BZ), is only a few tens of millielectronvolts, such that in the vicinity of these points, there is a quasilinear 3D Dirac dispersion [8][9][10]. Experimentally, angle-resolved photoemission spectroscopy [11], magnetotransport [12,13] and nuclear magnetic resonance [14] measurements have probed the possible 3D Dirac nature of the electrons in these compounds. Experiments have also revealed signatures of ferromagnetism arising from oxygen vacancies [15,16], high thermoelectric performance [17], superconductivity arising from Sr vacancies [18,19] and weak antilocalization due to spin-orbital entanglement [20].…”

Section: Introductionmentioning

confidence: 99%

Unusual valence state in the antiperovskites Sr3SnO and Sr3PbO revealed by x-ray photoelectron spectroscopy

Huang

Nakamura

Küster

et al. 2019

Phys. Rev. Materials

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The class of antiperovskite compounds A3BO (A = Ca, Sr, Ba; B = Sn, Pb) has attracted interest as a candidate 3D Dirac system with topological surface states protected by crystal symmetry. A key factor underlying the rich electronic structure of A3BO is the unusual valence state of B, i.e., a formal oxidation state of −4. Practically, it is not obvious whether anionic B can be stabilized in thin films, due to its unusual chemistry, as well as the polar surface of A3BO, which may render the growth-front surface unstable. We report X-ray photoelectron spectroscopy (XPS) measurements of single-crystalline films of Sr3SnO and Sr3PbO grown by molecular beam epitaxy (MBE). We observe shifts in the core-level binding energies that originate from anionic Sn and Pb, consistent with density functional theory (DFT) calculations. Near the surface, we observe additional signatures of neutral or cationic Sn and Pb, which may point to an electronic or atomic reconstruction with possible impact on putative topological surface states. * d.huang@fkf.mpg.de † hnakamur@uark.edu; Present address:

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ARPES studies of the inverse perovskite Ca3PbO : Experimental confirmation of a candidate 3D Dirac fermion system

Cited by 42 publications

References 63 publications

Negative ionic states of tin in the oxide superconductor Sr3−xSnO revealed by Mössbauer spectroscopy

Negative ionic states of tin in the oxide superconductor Sr3−xSnO revealed by Mössbauer spectroscopy

Normal-state properties of the antiperovskite oxide Sr3−xSnO revealed by Sn119 -NMR

Unusual valence state in the antiperovskites Sr3SnO and Sr3PbO revealed by x-ray photoelectron spectroscopy

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