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This content will become publicly available on March 26, 2019

Title: Enhanced Piezoelectric Response of AlN via CrN Alloying

Since AlN has emerged as an important piezoelectric material for a wide variety of applications, efforts have been made to increase its piezoelectric response via alloying with transition metals that can substitute for Al in the wurtzite lattice. We report on density functional theory calculations of structure and properties of the Cr xAl 1-xN system for Cr concentrations ranging from zero to beyond the wurtzite-rocksalt transition point. By studying the different contributions to the longitudinal piezoelectric coefficient, we propose that the physical origin of the enhanced piezoelectricity in Cr xAl 1-xN alloys is the increase of the internal parameter u of the wurtzite structure upon substitution of Al with the larger Cr ions. Among a set of wurtzite-structured materials, we find that Cr xAl 1-xN has the most sensitive piezoelectric coefficient with respect to alloying concentration. Based on these results, we propose that Cr xAl 1-xN is a viable piezoelectric material whose properties can be tuned via Cr composition. We support this proposal by combinatorial synthesis experiments, which show that Cr can be incorporated in the AlN lattice up to 30% before a detectable transition to rocksalt occurs. At this Cr content, the piezoelectric modulus d 33 is approximately 4more » times larger than that of pure AlN. This finding, combined with the relative ease of synthesis under nonequilibrium conditions, may position Cr xAl 1-xN as a prime piezoelectric material for applications such as resonators and acoustic wave generators.« less
 [1] ;  [2] ;  [2] ;  [1] ;  [3] ;  [1] ;  [2] ;  [1]
  1. Colorado School of Mines, Golden, CO (United States)
  2. Colorado School of Mines, Golden, CO (United States); National Renewable Energy Lab. (NREL), Golden, CO (United States)
  3. National Renewable Energy Lab. (NREL), Golden, CO (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 2331-7019; PRAHB2
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Physical Review Applied
Additional Journal Information:
Journal Volume: 9; Journal Issue: 3; Journal ID: ISSN 2331-7019
American Physical Society (APS)
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; synthesis; functional materials; density functional theory; physical vapor deposition
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1429585