The effect of pressure on phase selection during nucleation in undercooled bismuth

Yoon, Woo Young; Paik, Jong-Ah; LaCourt, D.; Perepezko, John H.

doi:10.1063/1.337599

Cited by 53 publications

(16 citation statements)

References 12 publications

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“…The fact that Bi-II melts independent of pressure (i.e., melting is associated with no change in density) further suggests that liquid L is structurally more closely related to Bi-II than Bi-I. Indeed, undercooled liquid L by droplet emulsion forms metastable crystals at ambient condition with structure that is distinct from that of Bi-I but similar to that of the monoclinic Bi-II phase (44). It is, therefore, likely that this peak represents a remnant of the bilayer-like units in liquid L, consistent with the two-step liquid model (41).…”

Section: Discussionmentioning

confidence: 96%

Deep melting reveals liquid structural memory and anomalous ferromagnetism in bismuth

Shu

Wang

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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As an archetypal semimetal with complex and anisotropic Fermi surface and unusual electric properties (e.g., high electrical resistance, large magnetoresistance, and giant Hall effect), bismuth (Bi) has played a critical role in metal physics. In general, Bi displays diamagnetism with a high volumetric susceptibility (∼10 −4 ). Here, we report unusual ferromagnetism in bulk Bi samples recovered from a molten state at pressures of 1.4-2.5 GPa and temperatures above ∼1,250 K. The ferromagnetism is associated with a surprising structural memory effect in the molten state. On heating, low-temperature Bi liquid (L) transforms to a more randomly disordered high-temperature liquid (L ) around 1,250 K. By cooling from above 1,250 K, certain structural characteristics of liquid L are preserved in L. Bi clusters with characteristics of the liquid L motifs are further preserved through solidification into the Bi-II phase across the pressure-independent melting curve, which may be responsible for the observed ferromagnetism.bismuth | high pressure | ferromagnetism | melt structure B ismuth (Bi) has played important roles in metal and condensed matter physics. The extremely low carrier density of Bi allows quantum limits of the Landau level to be studied under high magnetic field (1) and quantum size effects to be observed at ∼100-nm length scale (2). At ambient condition, Bi is known to crystallize in the rhombohedral A-7 type structure (space group R-3m, D 5 3d ), with the primitive unit cell containing two atoms at positions (u, u, u) and (−u, −u, −u). Each atom has three equidistant nearest neighbors tightly bonded at a distance of ∼3.062Å (3). The Bi4 motifs form puckered bilayers ( Fig. S1A) with a thickness of 1.59Å stacked along the rhombohedral [111] direction. The distance between adjacent bilayers is 2.35Å (4), slightly smaller than the next nearest distance of 3.512Å (5). Each atom's next nearest neighbors are in the adjacent bilayers, and the bonding within each bilayer is much stronger than the interbilayer bonding. As such, Bi exhibits rather complex interatomic binding, with coexisting covalent (within the bilayers), metallic, and weaker van der Waals-like (between bilayers) bonding (4).The phase diagram of Bi is rich and complex ( Fig. 1). At ambient pressure, Bi melts at 544 K (6) with a liquid-liquid transition at 1,010 K (7). With increasing pressure, Bi undergoes structural transitions in both solid and liquid states. The A-7 structured Bi-I phase transforms successively into the monoclinic (Bi-II), incommensurate host-guest (Bi-III), and body-centered cubic (Bi-V) phases (8-10) with increasing pressure to ∼6 GPa. On pressure release, these high-pressure metallic crystalline phases are unstable and revert to the Bi-I phase. Below ∼1.6 GPa, the melting temperature of Bi-I decreases with increasing pressure, a behavior similar to that of ice. Between 1.6 and 2.4 GPa (11), the solid just below melting is the Bi-II phase, which has a similar bilayer structure to that of Bi-I, except that the distance betwe...

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Section: Discussionmentioning

confidence: 96%

Deep melting reveals liquid structural memory and anomalous ferromagnetism in bismuth

Shu

Wang

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…The electrodes were then dried under vacuum at 120 • C for 3 h. Lithium powders, synthesized by the droplet emulsion technique (DET), were coated onto the electrodes [14]. The total weight of the lithium powder coating was 0.04 mg.…”

Section: Methodsmentioning

confidence: 99%

Electrochemical behavior of a lithium-pre-doped carbon-coated silicon monoxide anode cell

Seong

Kim²,

Yoon

2009

Journal of Power Sources

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“…Lithium powders were produced using a droplet emulsion technique. [7][8][9] The average diameter of the lithium powders was ϳ10 m while the range in the diameter was 5-15 m. The lithium powders were compacted to produce lithium powder electrodes using indirect pressing ͑Fig. 1͒.…”

Section: Methodsmentioning

confidence: 99%

Effect of the Amount of Discharge on the Morphological Changes of the Lithium Powders

Hong

Yoon

Cho³

et al. 2008

Electrochem. Solid-State Lett.

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This paper reports the effect of the level of discharge on the morphological changes in lithium powder particles after discharge followed by a charge sequence. Each pouch cell contained a lithium powder electrode as a working electrode and a lithium foil electrode as a counter electrode. Various amounts of discharge ͑dissolution process͒ or charge ͑deposition process͒ were tested at a uniform current density of 0.1 mA cm −2 , and scanning electron microscope images were examined to explain the dissolution and deposition behavior for each condition. The maximum amount of discharge required to keep the initial shape of the particle was investigated.Lithium metal is the most attractive anode material for highenergy power sources in lithium secondary batteries. However, dendritic growth on lithium metal electrodes leads to deterioration in the cycling efficiency as well as safety problems. Therefore, the suppression of dendritic growth on the Li surface is the most important issue in lithium metal secondary batteries. 1 It has been suggested that lithium metal powder electrodes can improve the problems mentioned above. The formation of dendrites during charging has been suppressed by increasing the surface area 2 and, as a result, has markedly improved the cycling efficiency. 3 The morphological changes and the deposition and dissolution behavior were examined by scanning electron microscopy ͑SEM͒. 4,5 However, the growth of dendrites can occur in lithium powder electrodes as well as lithium foil electrodes. The instability of concentration profiles result in dendrite formation in the lithium foil electrode. 6 This study examined the morphological behavior of Li powder during cycling and investigated the discharge ͑dissolution process͒ and charge ͑deposition process͒ conditions under which the morphology of the powder was kept intact ͑i.e., no dendrite formation occurs͒. ExperimentalEach pouch cell contained a lithium powder electrode and a lithium foil electrode. The lithium powder electrode was used as the working electrode; the foil was used as the counter electrode. Lithium powders were produced using a droplet emulsion technique. 7-9 The average diameter of the lithium powders was ϳ10 m while the range in the diameter was 5-15 m. The lithium powders were compacted to produce lithium powder electrodes using indirect pressing ͑Fig. 1͒. The pressure was set at 15 Mpa, and the dimensions of the lithium powder electrode were 10 mm in width, 10 mm in length, and 100 m in thickness. The porosity of the powder electrodes was 11.8%. 10,11 The electrolyte was a 1 M solution of LiClO 4 in a 1:1 mixture ͑w/w͒ of ethylene carbonate and dimethyl carbonate. A porous polypropylene film was used as the separator. The cells were manufactured in a glove box under a dry argon atmosphere at room temperature. Discharge/charge cycling was performed using a WBCS3000 cycler ͑Wonatech͒. Each discharge-and-charge cycle was performed by passing a discharge or charge of 3, 6, 9, 18, and 21 C cm −2 at 0.1 mA cm −2 , respectively. The SEM ima...

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The effect of pressure on phase selection during nucleation in undercooled bismuth

Cited by 53 publications

References 12 publications

Deep melting reveals liquid structural memory and anomalous ferromagnetism in bismuth

Deep melting reveals liquid structural memory and anomalous ferromagnetism in bismuth

Electrochemical behavior of a lithium-pre-doped carbon-coated silicon monoxide anode cell

Effect of the Amount of Discharge on the Morphological Changes of the Lithium Powders

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