Layered pnictide-oxide Na2Ti2Pn2O (Pn=As, Sb): a candidate for spin density waves

Yan, Xun-Wang; Lu, Zhong-Yi

doi:10.1088/0953-8984/25/36/365501

Cited by 26 publications

(46 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As in the case with BaTi2Sb2O, at EF, three d orbitals contribute significantly and the topology of FS is highly similar to that in BaTi2Sb2O. These predicted FS of BaTi2Pn2O is highly similar to that theoretically predicted in Na2Ti2Pn2O [25,32,45]. Experimentally, Song et al recently performed angle-resolved photoemission spectroscopy (ARPES) studies on Ba0.95Na0.05Ti2Sb2O single crystals and found the multiband electronic structure having electron and hole pockets, consistent with the theoretical studies [46].…”

Section: Electronic Structure Of Bati2pn2osupporting

confidence: 56%

Titanium Pnictide Oxide Superconductors

Yajima

2017

Condensed Matter

View full text Add to dashboard Cite

Abstract:In 2012, a novel superconductor BaTi 2 Sb 2 O was found in the layered titanium pnictide oxides ATi 2 Pn 2 O. A related superconductor BaTi 2 Bi 2 O was subsequently discovered in 2013. The structure of these materials consists of alternate stacking of superconducting Ti 2 Pn 2 O layers and Ba blocking layers, which is somewhat similar to high-T c cuprates since the Ti 2 Pn 2 O layer contains an anti-CuO 2 -type Ti 2 O square lattice. In addition to the structural similarity to the well-known high-T c superconductors, BaTi 2 Pn 2 O shows unique physical properties: two superconducting domes appear in the electronic phase diagram for solid solutions of BaTi 2 (Sb 1-x Bi x ) 2 O and a unique density-wave instability which coexists with superconductivity. In this short review, the early studies of titanium pnictide oxides, the discovery of novel superconductors BaTi 2 Pn 2 O, and recent progress are summarized.

show abstract

Section: Electronic Structure Of Bati2pn2osupporting

confidence: 56%

Titanium Pnictide Oxide Superconductors

Yajima

2017

Condensed Matter

View full text Add to dashboard Cite

show abstract

“…(a) A bicolinear type and (b) blocked checkerboard type SDW model [290, 291] (taken from [291]). (c)√2 × √2 × 1 superstructure as a result of CDW transition (taken from [292]).…”

Section: New Superconductorsmentioning

confidence: 99%

Section: New Superconductorsmentioning

confidence: 99%

Exploration of new superconductors and functional materials, and fabrication of superconducting tapes and wires of iron pnictides

Hosono

Tanabe

Takayama‐Muromachi

et al. 2015

Science and Technology of Advanced Materials

202

190

View full text Add to dashboard Cite

This review shows the highlights of a 4-year-long research project supported by the Japanese Government to explore new superconducting materials and relevant functional materials. The project found several tens of new superconductors by examining ∼1000 materials, each of which was chosen by Japanese experts with a background in solid state chemistry. This review summarizes the major achievements of the project in newly found superconducting materials, and the fabrication wires and tapes of iron-based superconductors; it incorporates a list of ∼700 unsuccessful materials examined for superconductivity in the project. In addition, described are new functional materials and functionalities discovered during the project.

show abstract

“…However, the origin of the density-wave remains controversial. While some calculations attribute the anomalies of their transport properties to a spin-density-wave (SDW) transition [4][5][6], most experiments rather favor a charge-densitywave (CDW) scenario [7,8]. Moreover, nuclear quadruple resonance (NQR) experiments show that the in-plane 4-fold symmetry at the Sb site is broken below the transition temperature in BaTi 2 Sb 2 O [9].…”

mentioning

confidence: 99%

New phase transition inNa2Ti2As2Orevealed by Raman scattering

et al. 2016

View full text Add to dashboard Cite

We performed a Raman scattering study of Na2Ti2As2O. We identified a symmetry breaking structural transition at around Ts = 150 K, which matches a large bump in the electrical resistivity. Several new peaks are detected below that transition. Combined with first-principles calculations, our polarization-dependent measurements suggest a charge instability driven lattice distortion along one of the Ti-O bonds that breaks the 4-fold symmetry and more than doubles the unit cell.PACS numbers: 74.25. Kc, 74.25.nd, 71.45.Lr Because their layered structure resembles both the copper oxide and the iron-based superconductors, special attention is devoted to the ATi 2 P n 2 O (A = Na 2 , Ba, P n = As, Sb, Bi) system [1], in particular regarding anomalies in their transport properties that may be caused by orders competing with superconductivity. Although the maximum T c reported among these compounds is only 6.1 K in Ba 1−x K x Ti 2 Sb 2 O (x = 0.12), their phase diagram points towards a competition between densitywave states and superconductivity [2,3]. However, the origin of the density-wave remains controversial. While some calculations attribute the anomalies of their transport properties to a spin-density-wave (SDW) transition [4][5][6], most experiments rather favor a charge-densitywave (CDW) scenario [7,8]. Moreover, nuclear quadruple resonance (NQR) experiments show that the in-plane 4-fold symmetry at the Sb site is broken below the transition temperature in BaTi 2 Sb 2 O [9]. Recently, neutron diffraction experiments suggest an "intra-unit-cell nematic charge order" in BaTi 2 As 2 O [10], which makes the titanium oxypnictides more intriguing.In this Rapid Communication we focus on Na 2 Ti 2 As 2 O, which has the highest CDW transition temperature among this series [11]. Previous optical spectroscopy measurements indicate two CDW transitions at 42 K and 320 K in this material [12], while there is only little known about the lattice dynamics. Our Raman scattering study of Na 2 Ti 2 As 2 O is supported by first-principles calculations of the vibration modes. We observe a total of 4 single-phonon modes predicted by our first-principles calculations in the high-temperature phase and 1 additional feature assigned to a doublephonon excitation. By doing temperature-dependent Raman measurements, we reveal a structural transition breaking the 4-fold symmetry at around T s = 150 K, which is consistent with a yet not understood anomaly in the electrical resistivity. Combining the results of * p.richard@iphy.ac.cn † dingh@iphy.ac.cn our experiments with calculations, we suggest that this structural transition does not rotate the high-symmetry axes but more than doubles the primitive cell.The Na 2 Ti 2 As 2 O single crystals used in our measurements were grown by the flux method [13]. Freshly grown plate-like samples with typical size of 1 × 2 × 0.06 mm 3 were prepared and electrodes were glued on them in a glove box for avoiding air contamination. The in-plane resistivity was measured using a commercial physical properties ...

show abstract

Layered pnictide-oxide Na₂Ti₂Pn₂O (Pn=As, Sb): a candidate for spin density waves

Cited by 26 publications

References 42 publications

Titanium Pnictide Oxide Superconductors

Titanium Pnictide Oxide Superconductors

Exploration of new superconductors and functional materials, and fabrication of superconducting tapes and wires of iron pnictides

New phase transition inNa2Ti2As2Orevealed by Raman scattering

Contact Info

Product

Resources

About