Bulk Superconductivity Below 6 K in PdBi2Te3 Topological Single Crystal

Abstract

We study the structural and bulk superconducting properties of self flux grown PdBi 2 Te 3 single crystal. Phase purity of as grown crystal is confirmed by Rietveld refinement of gently crushed powder XRD of the same. PdBi 2 Te 3 crystallizes in rhombohedral structure with R-3 m space group along with small impurity of Bi. Scanning Electron Microscopy (SEM) images showed layered structure and the elemental analysis by energy dispersive X Ray analysis (EDAX) done on same confirmed the stoichiometry to be near to PdBi 2 Te 3 . Characteristic vibrational modes viz. A 1 1g , Eg 2 , A 2 1g are clearly observed in Raman spectrum, and are slightly shifted from that as in case of Bi 2 Te 3 . Bulk superconductivity is confirmed by FC and ZFC magnetization measurements (M-T) exhibiting diamagnetic transition with T c onset at around 6K. M-H plots at different temperatures of 2K, 2.5K, 3K, 3.5K, 4K, 4.5K, 5K and 6K showed clear opening of the loop right up to 6K. Both M-T and M-H clearly establish the appearance of bulk type II superconductivity below 6K in studied PdBi 2 Te 3 . The lower critical field H c1 and upper critical field H c2 are at 180Oe at 4800Oe respectively at 2K for as grown PdBi 2 Te 3 crystal. Other critical parameters of superconductivity such as coherence length, penetration depth and kappa parameter are also calculated.

Raman spectroscopy of Bi2Se3-xTex (x = 0–3) topological insulator crystals

“…The quality of fit is estimated by  2 (parameter for the goodness of fit), which is estimated to be 2.49, 1.58, 5.62, 2.81, and 3.27for Bi 2 Se 3 , Bi 2 Se 2 Te, Bi 2 Se 1. 5 This gap provides the opportunity to intercalate a suitable element to get desired properties such as superconductivity [14,15], etc. It can be seen in unit cells of mixed TIs that the middle Se layer remains intact in all cases this is due to the high electronegativity of Se.The high electronegativity of selenium as compared to tellurium makes Se more ionic in nature and its tendency to attract more electrons from Bi 3+ makes Se(II) position more preferable for Se as it is bonded with two of Bi atoms.…”

Type-II superconductivity below 4K in Sn0.4Sb0.6

“…TS does show some distinct features such as hosting Majorana fermions [4], which are used in fault tolerant quantum computers [5]. Doping is a well-established method to induce superconductivity in bulk TIs like Bi 2 Se 3 , Bi 2 Te 3 as Bi 2 Se 3 , which care made superconducting by intercalation of Copper (Cu), Niobium (Nb), Strontium (Sr), Thallium (Tl) and Palladium (Pd) [6][7][8][9][10]. There are some binary alloys as well; containing heavy elements such as Bismuth (Bi) that shows topological non trivial behavior due to the presence of intrinsic spin orbit coupling (SOC) in these elements [11][12].…”

Metal doping in topological insulators- a key for tunable generation of terahertz

“…Interestingly, the presence of the Van der Waals gap in these materials makes these materials a good choice for element intercalation. Intercalation of elements such as Nb, Cu, Sr, Pd, and Tl have found to dope more carriers in Bi-based TIs and leads to the occurrence of Superconductivity [21,[25][26][27][28][29][30][31]. The effect of doping on electrical and magnetic properties of TIs is studied significantly, but its effect on the optical properties of TIs has not studied to that extent.…”