Possible superconductivity in the Bismuth IV solid phase under pressure

Abstract

The first successful theory of superconductivity was the one proposed by Bardeen, Cooper and Schrieffer in 1957. This breakthrough fostered a remarkable growth of the field that propitiated progress and questionings, generating alternative theories to explain specific phenomena. For example, it has been argued that Bismuth, being a semimetal with a low number of carriers, does not comply with the basic hypotheses underlying BCS and therefore a different approach should be considered. Nevertheless, in 2016 based on BCS we put forth a prediction that Bi at ambient pressure becomes a superconductor at 1.3 mK. A year later an experimental group corroborated that in fact Bi is a superconductor with a transition temperature of 0.53 mK, a result that eluded previous work. So, since Bi is superconductive in almost all the different structures and phases, the question is why Bi-IV has been elusive and has not been found yet to superconduct? Here we present a study of the electronic and vibrational properties of Bi-IV and infer its possible superconductivity using a BCS approach. We predict that if the Bi-IV phase structure were cooled down to liquid helium temperatures it would also superconduct at a Tc of 4.25 K.

Emergence of magnetism in bulk amorphous palladium

“…This, together with the overflow of electrons from the d shell to the sp shells may be an indicator of an unexpected behaviour. However, since identifying unambiguously the cutoff value to calculate the nn in amorphous metals is a controversial subject [10] we opted for a complementary, direct approach in a manner similar to our previous calculations on bismuth [16,17], and obtained the densities of electronic states with α spins and with β spins to see if they indicate a net magnetic moment, and they do, Fig. 4(a).…”

Could Negative Pressures Turn Bismuth into a Metal? The Case of the Expanded

“…A year after our prediction, experimentalists proved us correct and they found that the Wyckoff structure superconducts below 0.53 mK at ambient pressure [9]. We had ventured to estimate superconducting temperatures for bismuth under various conditions; for the crystalline phase, that had not been found to superconduct, we succeeded; our other predictions await verification [7,10]. So, with this succinct background we decided that bismuth was the ideal "guinea pig" to test the effect of negative pressures and we undertook the search to see if it could become metallic or a semiconductor under expansion, and what the possibilities were to find it in a superconducting state.…”

“…Bismuth was first found to be a superconductor when in the amorphous phase at ambient pressure [4,5]. Then, when the Wyckoff crystalline phase (the structure at room temperature and atmospheric pressure) was subjected to positive pressures it changed crystalline structures but maintained the superconducting properties for most of the new topologies (See [6] and [7], and references contained therein). Then we came into the play and predicted, using a simple BCS approach, that although the crystalline Wyckoff structure had not been found to superconduct, it should, for temperatures below 1.3 mK [8].…”

Nickel-(Bi,Ag) sulphide mineralization from NYF Vepice pegmatite, Milevsko pluton, southern Bohemia (Czech Republic) - a reflection of the parental granite chemistry

“…Mostly fine-grained aggregates of a single mineral or mixture of several sulphides, sulphosalts and/or native metals and their alloys (Cu, Pb, Zn, Cd, Bi, Ag, Sb, As, Te) are subsolidus in origin. Anhedral to subhedral grains, and aggregates of rather common native bismuth with the melting point about 260-270 °C (e.g., Živkovič and Živkovič 1996;Valladares et al 2018) is mostly among the earliest phases in these assemblages, and it suggests that sulphides crystallized at evidently lower T typically ~200-100 °C (e.g., Černý and Harris 1978;Márquez-Zavalía et al 2012). In contrast, crystallization of stannitegroup minerals, typical sulphides in granitic pegmatites (Kissin et al 1978;Černý et al 2001), proceeded at higher T ~400 °C.…”

“…Argentopentlandite, pentlandite and parkerite occur only on a microscopic scale as irregular aggregates and inclusions in major and minor sulphides. The temperature of the crystallization of sulphides is constrained by the textural relations and mineral assemblage: polysynthetic twinning of chalcopyrite suggests the transformation of high-temperature cubic chalcopyrite to tetragonal one at T = 550 °C (Kostov and Stefanova 1981;Čvileva et al 1988); sphalerite stars in chalcopyrite indicate T ~500-400 °C (Kostov and Stefanova 1981;Sugaki et al 1987), argentopentlandite has the upper limit of T < 455 o C (Mandziuk and Scott 1977), marcasite has the upper-temperature stability limit at T = ~240 °C (Murowchick 1992), and native bismuth as the late mineral suggests T < ~270 °C (melting point 271 °C, Živkovič and Živkovič 1996; T = 267 to 250 ºC at P = 1 to 5 kbar, Valladares et al 2018). Early sulphides (pyrrhotite, chalcopyrite, sphalerite, argentopentlandite) crystallized at T < ~400-450 °C, whereas pyrite, marcasite, galena, parkerite, and native Bi at T < 240 °C.…”