First-principles simulated-annealing study of phase transitions and short-range order in transition-metal and semiconductor alloys

Journal Article · Thu Sep 01 00:00:00 EDT 1994 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.50.6642· OSTI ID:6961195

Lu, Z W; Laks, D B; Wei, S; Zunger, A ^[1]

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1. National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)

Total-energy local-density calculations on approximately 20 periodic crystal structures of a given [ital AB] compound are used to define a long-range Ising Hamiltonian which correctly represents atomic relaxations. This allows us to accurately calculate structural energies of [ital relaxed] substitutional [ital A][sub 1[minus][ital x]][ital B][sub [ital x]] systems containing thousands of transition-metal atoms, simply by adding up spin products in the Ising Hamiltonian. The computational cost is thus size independent. We then apply Monte Carlo and simulated-annealing techniques to this Ising Hamiltonian, finding (i) the [ital T]=0 ground-state structures, (ii) the order-disorder transition temperatures [ital T][sub [ital c]], and (iii) the [ital T][gt][ital T][sub [ital c]] short-range-order parameters. The method is illustrated for a transition-metal alloy (Cu[sub 1[minus][ital x]]Pd[sub [ital x]]) and a semiconductor alloy (Ga[sub 1[minus][ital x]]In[sub [ital x]]P). It extends the applicability of the local-density method to finite temperatures and to huge substitutional supercells. We find for Cu[sub 0.75]Pd[sub 0.25] a characteristic fourfold splitting of the diffuse scattering intensity due to short-range order as observed experimentally.

• DOE Contract Number: AC36-83CH10093
• OSTI ID: 6961195
• Journal Information: Physical Review, B: Condensed Matter; (United States), Vol. 50:10; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COPPER BASE ALLOYS
ORDER-DISORDER TRANSFORMATIONS
GALLIUM PHOSPHIDES
INDIUM PHOSPHIDES
PALLADIUM ALLOYS
SEMICONDUCTOR MATERIALS
TRANSITION ELEMENT ALLOYS
ALLOYS
CRYSTAL STRUCTURE
GROUND STATES
STOICHIOMETRY
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE ZERO K
COPPER ALLOYS
ENERGY LEVELS
GALLIUM COMPOUNDS
INDIUM COMPOUNDS
MATERIALS
PHASE TRANSFORMATIONS
PHOSPHIDES
PHOSPHORUS COMPOUNDS
PLATINUM METAL ALLOYS
PNICTIDES
TEMPERATURE RANGE
360102* - Metals & Alloys- Structure & Phase Studies