<i>Ab initio</i>molecular dynamics study of the static, dynamic, and electronic properties of liquid Bi near melting using real-space pseudopotentials

Souto, José A.; Alemany, M. M. G.; Gallego, L. J.; González, L.; González, D. J.

doi:10.1103/physrevb.81.134201

Cited by 36 publications

(55 citation statements)

References 63 publications

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“…3 B and C) is also consistent with the proposed liquid-liquid transition. The small peak q 1 at ∼2.9Å −1 was previously interpreted as a signature of a short-lived diatomic molecular unit (Bi2) in liquid state according to ab initio molecular dynamics calculations on small clusters of Bi atoms at 600 K (40). However, if the formation of the Bi2 units were caused by the breakup of larger structural units (such as the bilayers), which are related to the low-temperature crystalline phase, then the population of Bi2 should increase with temperature, because the liquid is expected to be more disordered.…”

Section: Discussionmentioning

confidence: 99%

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: 99%

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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“…11,25 Its absence at higher temperatures reflects the increasing importance of diffusive (g) modes as the temperature increases. They make up 29% of the total at 573 K, increasing to 42% at 1023 K. At frequencies above 3-4 meV, the vibrational component dominates, showing a distinct peak around 9 meV at 573 K that moves to slightly lower frequencies at higher temperatures.…”

Section: A Power Spectrum and Thermodynamicsmentioning

confidence: 99%

“…Simulations with 2000 ions have been performed with this approach in Si (50 ps data collection, 1740 K), 7 Ga (80 ps, three temperatures), 9 and Mg (50 ps, 953 K). 10 Calculations using DF/MD calculations without approximations to the non-interacting kinetic energy have been limited, however, to Sn (64 atoms, 108 ps, three temperatures), 13 Bi (124 atoms, 40 ps, 600 K), 11 and Fe (120 atoms, 40 ps, 1873 K). 17 In addition to having a larger fraction of atoms close a) Electronic mail: r.jones@fz-juelich.de to a neighboring cell (larger "finite size effects"), small simulation cells mean that the lowest wave-vector that can be considered (2π/L for a cubic cell of side L) is correspondingly larger.…”

Section: Introductionmentioning

confidence: 99%

“…Parallel to these developments there have been detailed studies of the static, dynamic, and electronic properties of liquids using molecular dynamics (MD) simulations, often with the density functional (DF) theory 6 as the basis of force and energy calculations. These have included studies of Si, 7,8 Ga, 2,9 Mg, 10 Bi, 11,12 Sn, 13 Pb, 14 and Al 15 as well as 58 liquid elements at their triple points (125 atoms in the simulation cell, except for Li, Na, Mg, and Al with 250-384 atoms). 16 The computational demands presented by DF/MD calculations have led to the use of a number of simplifying assumptions.…”

Section: Introductionmentioning

confidence: 99%

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Collective excitations and viscosity in liquid Bi

Ropo

Akola

Jones

2016

The Journal of Chemical Physics

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Liquid structure and temperature invariance of sound velocity in supercooled Bi melt J. Chem. Phys. 140, 094502 (2014) The analysis of extensive density functional/molecular dynamics simulations (over 500 atoms, up to 100 ps) of liquid bismuth at four temperatures between 573 K and 1023 K has provided details of the dynamical structure factors, the dispersion of longitudinal and transverse collective modes, and related properties (power spectrum, viscosity, and sound velocity). Agreement with available inelastic x-ray and neutron scattering data and with previous simulations is generally very good. The results show that density functional/molecular dynamics simulations can give dynamical information of good quality without the use of fitting functions, even at long wavelengths. Published by AIP Publishing.[http://dx

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“…The structure of liquid Bi has been well studied and most researchers [12,13] pointed out that this element has the structure different than close packed metals. The main difference is in the existence of a shoulder on the right hand side of the structure factor (SF) and a smaller number of neighbors, which according to the results of different authors lies within the range of 7.5 to 9.0 at a temperature close to the melting point.…”

Section: Introductionmentioning

confidence: 99%

Structure and thermal expansion of liquid bismuth

Mudry

Shtablavyi

Liudkevych

et al. 2015

Materials Science-Poland

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Experimental structural data for liquid Bi were used for estimation of the main structure parameters as well as the thermal expansion coefficient both in supercooled and superheated temperature ranges. It was shown that the equilibrium melt had a positive thermal expansion coefficient within a temperature range upon melting and a negative one at higher temperatures. The former was related to structure changes upon melting, whereas the latter with topologic disordering upon further heating. It was found that the superheated melt had a negative thermal expansion coefficient. The results obtained from structural data were compared with the thermal expansion coefficient calculated from the data of density for liquid Bi.

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Ab initiomolecular dynamics study of the static, dynamic, and electronic properties of liquid Bi near melting using real-space pseudopotentials

Cited by 36 publications

References 63 publications

Deep melting reveals liquid structural memory and anomalous ferromagnetism in bismuth

Deep melting reveals liquid structural memory and anomalous ferromagnetism in bismuth

Collective excitations and viscosity in liquid Bi

Structure and thermal expansion of liquid bismuth

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