Virtual-crystal approximation that works: Locating a compositional phase boundary in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="normal">Pb</mml:mi><mml:mo>(</mml:mo><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Zr</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mi>−</mml:mi><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ti</mml:mi></mml:mrow><mml:mrow><mml:mi>x</mml:mi></mml:mr

Ramer, Nicholas J.; Rappe, Andrew M.

doi:10.1103/physrevb.62.r743

Cited by 156 publications

(53 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In Fig. 5, the green solid line reports the prediction of the Virtual-crystal approximation (VCA) 38 for the cation-oxygen distances, calculated as the linear interpolation between the average Pr-O and Y-O distances. The chemical disorder in a solid solution can be theoretically simulated by using first-principles calculation.…”

Section: B Exafs Data Analysismentioning

confidence: 99%

See 1 more Smart Citation

X-ray diffraction and extended X-ray absorption fine structure study of epitaxial mixed ternary bixbyite PrxY2−xO3 (x = 0–2) films on Si (111)

Niu

Zoellner

Zaumseil

et al. 2013

Journal of Applied Physics

View full text Add to dashboard Cite

Ternary single crystalline bixbyite PrxY2−xO3 films over the full stoichiometry range (x = 0–2) have been epitaxially grown on Si (111) with tailored electronic and crystallographic structure. In this work, we present a detailed study of their local atomic environment by extended X-ray absorption fine structure at both Y K and Pr LIII edges, in combination with complementary high resolution x-ray diffraction measurements. The local structure exhibits systematic variations as a function of the film composition. The cation coordination in the second and third coordination shells changes with composition and is equal to the average concentration, implying that the PrxY2−xO3 films are indeed fully mixed and have a local bixbyite structure with random atomic-scale ordering. A clear deviation from the virtual crystal approximation for the cation-oxygen bond lengths is detected. This demonstrates that the observed Vegard's law for the lattice variation as a function of composition is based microscopically on a more complex scheme related to local structural distortions which accommodate the different cation–oxygen bond lengths.

show abstract

Section: B Exafs Data Analysismentioning

confidence: 99%

“…A direct way is to use as large as possible supercells with periodic boundary conditions so that inhomogeneities can be incorporated into perfectly periodic systems, an approach which is, however quite computationally demanding. 38 TABLE I. Average Y K edge distances.…”

Section: B Exafs Data Analysismentioning

confidence: 99%

X-ray diffraction and extended X-ray absorption fine structure study of epitaxial mixed ternary bixbyite PrxY2−xO3 (x = 0–2) films on Si (111)

Niu

Zoellner

Zaumseil

et al. 2013

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…Mean-field methods, such as the virtual crystal approximation, do reproduce the properties in systems in which an averaging approach can be employed [9,10]. However, it is well known that variations in shortranged chemical ordering, which are not expressed by these chemical averaging methods, play an important role in defining the behavior and properties of complex oxide ferroelectrics * coopervr@ornl.gov † sbeckman@iastate.edu [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Special quasirandom structures to study the(K0.5Na0.5)NbO3random alloy

et al. 2014

View full text Add to dashboard Cite

The local structure of K0.5Na0.5NbO3 is investigated using first-principles methods with an optimized special quasirandom structure (SQS). Through a comparison of the computed pair distribution functions with those from neutron powder diffraction data, the SQS approach demonstrates its ability to accurately capture the local structure patterns derived from the random distribution of K and Na on the perovskite Asite. Using these structures, local variations in Na-O interactions are suggested to be the driving force behind the R3c to Pm phase transition. A comparison between the SQS and a rocksalt structure shows the inability of the latter to account for the local variability present in a random solid solution. As such, the predictive nature of the SQS demonstrated here suggests that this approach may provide insight in understanding the properties of a wide range of bulk oxide alloys or solid solutions. Disciplines Polymer and Organic Materials | Process Control and Systems | Structural Materials CommentsThis article is from Physical Review B 90 (2014) The local structure of K 0.5 Na 0.5 NbO 3 is investigated using first-principles methods with an optimized special quasirandom structure (SQS). Through a comparison of the computed pair distribution functions with those from neutron powder diffraction data, the SQS approach demonstrates its ability to accurately capture the local structure patterns derived from the random distribution of K and Na on the perovskite A-site. Using these structures, local variations in Na-O interactions are suggested to be the driving force behind the R3c to P m phase transition. A comparison between the SQS and a rocksalt structure shows the inability of the latter to account for the local variability present in a random solid solution. As such, the predictive nature of the SQS demonstrated here suggests that this approach may provide insight in understanding the properties of a wide range of bulk oxide alloys or solid solutions.

show abstract

“…13 The popular generalized gradient approximation 14 is employed to optimize the volume and the internal atomic coordinates. To simulate doping, we use the virtual crystal approximation 15 and rigid band approach. 16,17 This approximation is widely employed in calculations of transport properties of doped semiconductors and is accurate when the doping is not too large.…”

Section: Computational Methods and Resultsmentioning

confidence: 99%

Thermoelectric performance of electron and hole doped PtSb2

Saeed

Singh

Parker

et al. 2013

Journal of Applied Physics

View full text Add to dashboard Cite

We investigate the thermoelectric properties of electron and hole doped PtSb 2 . Our results show that for doping of 0.04 holes per unit cell (1:5 Â 10 20 cm À3 ) PtSb 2 shows a high Seebeck coefficient at room temperature, which can also be achieved at other temperatures by controlling the carrier concentration (both electron and hole). The electrical conductivity becomes temperature independent when the doping exceeds some 0.2 electrons/holes per unit cell. The figure of merit at 800 K in electron and hole doped PtSb 2 is comparatively low at 0.13 and 0.21, respectively, but may increase significantly with As alloying due to the likely opening of a band gap and reduction of the lattice thermal conductivity. V C 2013 AIP Publishing LLC. [http://dx

show abstract

Virtual-crystal approximation that works: Locating a compositional phase boundary inPb(Zr1−xTix

Cited by 156 publications

References 26 publications

X-ray diffraction and extended X-ray absorption fine structure study of epitaxial mixed ternary bixbyite PrxY2−xO3 (x = 0–2) films on Si (111)

X-ray diffraction and extended X-ray absorption fine structure study of epitaxial mixed ternary bixbyite PrxY2−xO3 (x = 0–2) films on Si (111)

Special quasirandom structures to study the(K0.5Na0.5)NbO3random alloy

Thermoelectric performance of electron and hole doped PtSb2

Contact Info

Product

Resources

About