Coexistence of multiple metastable polytypes in rhombohedral bismuth

Shu, Yu; Hu, Wentao; Liu, Zhongyuan; Shen, Guoyin; Xu, Bin; Zhao, Zhisheng; He, Jingliang; Wang, Yanbin; Tian, Yongjun

doi:10.1038/srep20337

Cited by 19 publications

(13 citation statements)

References 42 publications

(56 reference statements)

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“…In the 30 × 30-nm 2 area shown in Fig. S8, numerous domains of various polytypes are observed that have close similarity to the A-7 structure (38). Crystal lattice varies smoothly across the domains with poorly defined domain boundaries.…”

Section: Physicsmentioning

confidence: 94%

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: Physicsmentioning

confidence: 94%

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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“…166,

R \overset{3}{true} m).

49,50 That structure comes from the transformation of simple cubic structure via two separate distortions including trigonal shear and relative displacement 51‐53 . Moreover, mosaic structures of Bi consisted of one monoclinic (M) and two triclinic structures (T1 and T2) 54 . They might be formed through the tiny lattice distortion of A7 structure and they coexist with the A7 structure 55 .…”

Section: Structural Of Bismuth‐based Photocatalytic Materialsmentioning

confidence: 99%

“…2

(P \overset{1}{true}

), and No. 2 (P1) in space groups were assigned to A7, M, T1, and T2 structures, respectively 54,56,57 . The unique electronic band feature of Bi is the existence of a small overlap between conduction band at the L points of the Brillouin zone and valence band at the T points (T and L points would have been equivalent in nondistorted f.c.c lattice).…”

Section: Structural Of Bismuth‐based Photocatalytic Materialsmentioning

confidence: 99%

Bi‐based photocatalysts for light‐driven environmental and energy applications: Structural tuning, reaction mechanisms, and challenges

Chen

Liu

Cui

et al. 2020

EcoMat

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Environmental pollution and energy crisis have become major challenges to sustainable development of human society. Solar-driven photocatalytic technology is regarded as an extremely attractive solution to environmental remediation and energy conversion. Unfortunately, practical applications of traditional photocatalysts are restricted owing to the poor absorption of visible light, insufficient charge separation and undefined reaction mechanism. Therefore, developing novel visible light photocatalysts and exploring their modification strategies are significant in the area of photocatalysis. Bi-based photocatalysts have attracted wide attention due to unique geometric structures, tunable electronic structure and decent photocatalytic activity under visible light. At present, Bi-based photocatalysts can be mainly classified as bismuth metal, binary oxides, bismuth oxyhalogen, multicomponent oxides and binary sulfides, and so forth. Although they can be used as independent photocatalysts for environmental purification and energy development, their efficiency is not ideal. Therefore, many efforts have been made to enhance their photocatalytic performance in the past few decades. Significant progresses in determining the fundamental properties of photocatalysts, improving the photocatalytic performance and understanding the photocatalytic mechanism in important reactions have been made benefited from the various new developed concepts and approaches. This review introduces the structural properties of Bi-based photocatalysts in detail and summarizes the design and modification strategy for improving the photocatalytic performance, including metal/ Peng Chen and Hongjing Liu contributed equally to this work.

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“…Under ambient condition, Bi is commonly designated as a rhombohedral lattice (space group R-3m, so-called arsenic or A7 structure), which is characterized by a pair of atoms spaced non-equidistantly along the trigonal axis in a Peierls distortion of the simple cubic structure 47,48 . Alternatively, the structure of Bi can be described as a hexagonal lattice with six atoms per unit cell, or as a pseudo-cubic structure with one atom per unit cell 49 .…”

Section: Crystal Growth and Characterizationmentioning

confidence: 99%

Evidence for bulk superconductivity in pure bismuth single crystals at ambient pressure

Prakash

Kumar

Thamizhavel

et al. 2017

Science

158

125

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At ambient pressure, bulk rhombohedral bismuth is a semimetal that remains in the normal state down to at least 10 millikelvin. Superconductivity in bulk bismuth is thought to be unlikely because of the extremely low carrier density. We observed bulk superconductivity in pure bismuth single crystals below 0.53 millikelvin at ambient pressure, with an estimated critical magnetic field of 5.2 microteslas at 0 kelvin. Superconductivity in bismuth cannot be explained by the conventional Bardeen-Cooper-Schrieffer theory because its adiabatic approximation does not hold true for bismuth. Future theoretical work will be needed to understand superconductivity in the nonadiabatic limit in systems with low carrier densities and unusual band structures, such as bismuth.

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Coexistence of multiple metastable polytypes in rhombohedral bismuth

Cited by 19 publications

References 42 publications

Deep melting reveals liquid structural memory and anomalous ferromagnetism in bismuth

Deep melting reveals liquid structural memory and anomalous ferromagnetism in bismuth

Bi‐based photocatalysts for light‐driven environmental and energy applications: Structural tuning, reaction mechanisms, and challenges

Evidence for bulk superconductivity in pure bismuth single crystals at ambient pressure

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