Bulk superconductivity in single-phase Bi₃ O₂ S₃

Abstract

We report the synthesis of single phase Bi 3 O 2 S 3 sample and confirm the occurrence of bulk superconductivity with transition temperature at 5.8 K. The Bi 3 O 2 S 3 superconductor is categorized as the typical type-II superconductor based on the results of both temperature and magnetic field dependences of magnetization. Hall coefficient measurements give evidence of a multiband character, with a dominant conduction mainly by electron-like charge carriers. The charge carrier density is about 1.45 × 10 19 cm 3 , suggesting that the system has very low charge carrier density. This is the caption of the optional abstract figure. If there is no figure here, the abstract text should be divided into both columns.Copyright line will be provided by the publisher 1Introduction Materials with layered structure have been intensively studied as a promising approach to the exploration of new superconductors, since the discovery of cuprate superconductors [1]. This approach has become more convincing due to the discovery of iron-based superconductors [2], which have a layered structure consisting of the so-called superconducting layers (Fe 2 M 2 layers, M=P, As, Se, or Te) and blocking charge reservoir layers [3,4]. Superconductivity occurs when charge carriers are generated in blocking layers and transferred into the superconducting layers.Recently [13]. They claim that if the majority phase is Bi 3 O 2 S 3 , the sample exhibits superconducting transition at 4.5 K. The superconductivity is rapidly suppressed as the Bi 2 OS 2 -like stacking faults are introduced in Bi 3 O 2 S 3 . This report is interesting in the exploration of new superconducting materials. However, due to the lack of single phase sample, the superconductivity in Bi 3 O 2 S 3 remains to be controversial. In this Letter, we report the successful synthesis of single phase Bi 3 O 2 S 3 and bulk superconductivity with transition temperature at 5.8 K.2 Experimental Polycrystalline sample of Bi 3 O 2 S 3 was synthesized by a conventional solid state reaction method. High-purity starting materials of Bi 2 O 3 and S were weighed with nominal composition Bi 12 O 18 S 13 and thoroughly ground in an agate mortar. It should be noted that the nominal S content is higher than that in ref. 13. The mixed power was pressed into pellets, sealed in evacuated quartz tubes and then placed in a preheated furnace at 430°C. After being heated for 2 h, the sample was quenched down to 0°C by putting the quartz tubes into ice water. It should be very careful when the products were removed from the sealed quartz tubes as large amount of S-O gas (such as SO 2 and O 2 ) was produced during heating.

Superconductivity in semimetallicBi3O2S3

“…Firstly, this inferred carrier concentration is the same as found in the prior work (Ref. [9]), and were this simply a semiconductor such a coincidence in extrinsic doping levels would seem rather unlikely. Secondly, and more compellingly, the thermopower data presented in Fig.…”

“…Polycrystalline sample of Bi 3 O 2 S 3 was prepared by a conventional solid state reaction method according to the literature precedent [8,9]. The Bi 2 O 3 powders and S pieces were weighed by targeting "Bi 12 O 18 S 13 ", fully mixed, ground and then pressed into pellets.…”

“…Theoretical tight-binding calculations on a similar BiS 2 -layer-based system of LaOBiS 2 (F-doping; T c = 10.6 K) [5] shows that dominating bands for electron conduction and superconductivity are those derived from four Bi 6p-S 3p orbitals that give nearly half-filled, electron-hole symmetric, quasi-one-dimensional bands [6] that give nesting of the Fermi surface. Other members of Bi-O-S system include Bi 6 O 8 S 5 [7], and Bi 3 O 2 S 3 [8,9]. Most recently, critical temperature at T c = 4.5 K was discovered in Bi 3 O 2 S 3 [8] that appeared, based on that work, to be a typical type-II superconductor with T c onset = 5.8 K, upper critical field of H c2 = 4.8 T and low electron-dominant carriers of ~ 10 19 cm -3 [9].…”

“…Other members of Bi-O-S system include Bi 6 O 8 S 5 [7], and Bi 3 O 2 S 3 [8,9]. Most recently, critical temperature at T c = 4.5 K was discovered in Bi 3 O 2 S 3 [8] that appeared, based on that work, to be a typical type-II superconductor with T c onset = 5.8 K, upper critical field of H c2 = 4.8 T and low electron-dominant carriers of ~ 10 19 cm -3 [9]. This manuscript focuses on Bi 3 O 2 S 3 by advancing investigations into reasons of superconductivity through theoretical calculations and bulk thermodynamic and transport property results.…”

Unusual Mixed Valence of Eu in Two Materials—EuSr2Bi2S4F4 and Eu2SrBi2S4F4: Mössbauer and X-ray Photoemission Spectroscopy Investigations

“…We have successfully synthesized two new Eu-based compounds, Eu2SrBi2S4F4 and EuSr2Bi2S4F4, derived from Eu3Bi2S4F4 and studied their structural, electrical and magnetic 3 properties. More specifically, we have investigated the phenomenon of valence fluctuations of europium, using 151 Eu-Mössbauer and XPS techniques, which Eu-ions occupying specific crystallographic 2a-sites in these materials exhibit.…”