Phonon Instabilities in fcc and bcc Tungsten

Journal Article · Mon Sep 01 00:00:00 EDT 1997 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.79.2073· OSTI ID:542298

Einarsdotter, K; Sadigh, B; Grimvall, G; Ozolins, V ^[1]

---

1. Department of Theoretical Physics, Royal Institute of Technology, SE-100 44 Stockholm (Sweden)

The lattice dynamics of bcc and fcc W is studied as a function of pressure using the density-functional linear-response theory. At high pressures and T=0 K, bcc W has a higher enthalpy than the fcc and hcp phases and it develops phonon softening anomalies related to this thermodynamic instability; however, it remains dynamically stable. In contrast, the widely unstable shear modes of fcc W at zero pressure (when H{sup fcc}{sub W}{gt}H{sup bc c}{sub W} ) stabilize with increasing pressure before H{sup fcc}{sub W}{lt}H{sup bc c}{sub W} . Hence the thermodynamic and dynamic instabilities are uncorrelated. {copyright} {ital 1997} {ital The American Physical Society}

• OSTI ID: 542298
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 11 Vol. 79; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BCC LATTICES
FCC LATTICES
INSTABILITY
LATTICE PARAMETERS
PHONONS
PRESSURE DEPENDENCE
SHEAR
TUNGSTEN