Structural and electrical properties of beryllium metal to 66 GPa studied using designer diamond anvils

Velisavljevic, Nenad; Chesnut, Gary N.; Vohra, Yogesh K.; Weir, Samuel T.; Malba, Vincent; Akella, Jagannadham

doi:10.1103/physrevb.65.172107

Cited by 28 publications

(31 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Beryllium at high pressure has been the subject of several experimental [6][7][8][9][10][11][12][13][14][15][16][17][18][19] and theoretical studies. [2][3][4][5][20][21][22] At ambient conditions beryllium is a metal with a hexagonal close packed (hcp) crystal structure (α phase) and a c/a ratio of 1.56, 23 far from the ideal value of 1.633.…”

Section: Introductionmentioning

confidence: 99%

“…While several high-pressure electrical conductivity studies observed changes interpreted as the α-β transition, 17, 26 recent x-ray diffraction studies have found no such transitions. 10,16 Theoretical efforts have found beryllium to be a challenging system, with predictions of the α-β phase line varying from 20 to 200 GPa. 4,5,21,27 Thus previous studies have reported widely varying results.…”

Section: Introductionmentioning

confidence: 99%

“…Recent studies of beryllium have addressed some of the controversial aspects of earlier work, 10,16 but several questions remain. X-ray synchrotron studies of beryllium have established the stability of the hcp structure at room temperature to pressures approaching 200 GPa.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

X-ray diffraction and Raman studies of beryllium: Static and elastic properties at high pressures

et al. 2005

View full text Add to dashboard Cite

We report combined x-ray and Raman studies of beryllium in helium or argon pressure medium at pressures approaching 200 GPa. Our results are generally consistent with recent studies confirming the stability of the hexagonal close-packed phase to the highest pressures. However, the quasi-hydrostatic conditions of our studies lead to a stiffer equation of state (K 0 =109.88, K 0 '=3.59) and a gradual approach toward a more ideal c/a ratio of 1.60 at 180 GPa. Combining our Raman and EOS data, we are able to evaluate the pressure dependence of the elastic shear modulus (We discuss the comparison of our results with measurements using ultrasonic and dynamic techniques.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

X-ray diffraction and Raman studies of beryllium: Static and elastic properties at high pressures

et al. 2005

View full text Add to dashboard Cite

show abstract

“…Near the melting temperature T M (∼ 1, 550 K at 0 GPa), a competing phase with the body-centered cubic symmetry (bcc) seems to emerge [4][5][6]. However, not all experiments [7][8][9][10][11][12][13] have observed this bcc phase, causing confusion and controversies. Be is important for both fundamental research [14][15][16][17] and practical applications.…”

mentioning

confidence: 99%

Premelting hcp to bcc Transition in Beryllium

Sun

Zhang

et al. 2017

Phys. Rev. Lett.

View full text Add to dashboard Cite

Beryllium (Be) is an important material with wide applications ranging from aerospace components to X-ray equipments. Yet a precise understanding of its phase diagram remains elusive. We have investigated the phase stability of Be using a recently developed hybrid free energy computation method that accounts for anharmonic effects by invoking phonon quasiparticles. We find that the hcp → bcc transition occurs near the melting curve at 0 < P < 11 GPa with a positive Clapeyron slope of 41 ± 4 K/GPa. The bcc phase exists in a narrow temperature range that shrinks with increasing pressure, explaining the difficulty in observing this phase experimentally. This work also demonstrates the validity of this theoretical framework based on phonon quasiparticle to study structural stability and phase transitions in strongly anharmonic materials.PACS numbers: 63.20. Ry, 81.30.Bx, 61.50.Ks,Elemental solids usually undergo a series of phase transitions from ambient conditions to extreme conditions [1][2][3]. Knowledge of their phase diagrams is a prerequisite for establishing their equations of state (EOS), a fundamental relation for determining thermodynamics properties and processes at high pressures and temperatures (PT). However, resolving phase boundaries is challenging for experiments given the uncertainties from several sources, especially at very high PT. Beryllium (Be) is a typical system whose phase diagram remains an open problem despite intense investigations. It assumes a hexagonal close-packed (hcp) structure at relatively low T [1]. Near the melting temperature T M (∼ 1, 550 K at 0 GPa), a competing phase with the body-centered cubic symmetry (bcc) seems to emerge [4][5][6]. However, not all experiments [7][8][9][10][11][12][13] have observed this bcc phase, causing confusion and controversies. Be is important for both fundamental research [14][15][16][17] and practical applications. Being a strong and light-weight metal, it has been widely used in a broad range of technological applications in harsh environments and extreme PT conditions, e.g., up to T > 4,000 K and P > 200 GPa [18][19][20][21][22].The bcc phase of Be was directly observed [4,5] only at T > 1, 500 K around ambient pressure before melting. Measurements of the temperature dependent resistance suggested that bcc Be is a high pressure phase and the hcp/bcc phase boundary between 0 < P < 6 GPa has a negative Clapeyron slope (−52 ± 8 K/GPa) [6]. However, recent experiments have challenged this conclusion [8,9,[11][12][13]. For example, it was reported that bcc Be was not observed for 8 < P < 205 GPa and 300 < T < 4, 000 K [13]. On the theory side, the study of Be's phase diagram using conventional methods encounters significant difficulties. The lattice dynamics of bcc Be is highly anharmonic, and the widely used quasi-harmonic approximation (QHA) and Debye model are not able to capture such effect [23][24][25][26][27][28][29]. For this reason, bcc Be and the associated hcp/bcc phase transition remain poorly understood for P < 11 GPa (density < 2.1g/...

show abstract

“…Beryllium with a distorted hcp atomic arrangement (6 þ 6 coordination) at ambient conditions is reported to show a structural distortion in the pressure range from 8.6 up to 14.5 GPa [27] while in an independent investigation the hexagonal modification is reported to be stable up to 66 GPa [28]. The c/a ratio of 1.568 deviates strongly from that of an ideal hcp arrangement (1.633) and remains almost constant upon pressure increase, a behaviour which is in sharp contrast to the findings for the heavier homologue barium.…”

Section: Alkali Metalsmentioning

confidence: 99%

Metallic high-pressure modifications of main group elements

Schwarz¹

2004

Zeitschrift Für Kristallographie - Crystalline Materials

View full text Add to dashboard Cite

Abstract. The high-pressure structural chemistry of main group elements in the metallic state is reviewed under consideration of more recent determinations of atomic arrangements with to some extend unexpected complexity. Following the concept of the pressure-coordination rule, the number of nearest neighbours is employed as a guiding quantity to reveal systematic trends. Violations of the rule will be mainly discussed in the light of electronic ground state changes upon compression.

show abstract

Structural and electrical properties of beryllium metal to 66 GPa studied using designer diamond anvils

Cited by 28 publications

References 13 publications

X-ray diffraction and Raman studies of beryllium: Static and elastic properties at high pressures

X-ray diffraction and Raman studies of beryllium: Static and elastic properties at high pressures

Premelting hcp to bcc Transition in Beryllium

Metallic high-pressure modifications of main group elements

Contact Info

Product

Resources

About