Sai N, Meyer B, Vanderbilt D
Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854-8019, USA.
Phys Rev Lett. 2000 Jun 12;84(24):5636-9. doi: 10.1103/PhysRevLett.84.5636.
Cubic perovskite compounds of the form (A(1/3)A(')(1/3)A(")(1/3))BO3 and A(B(1/3)B(')(1/3)B(")(1/3))O3, in which the differentiated cations form an alternating series of monolayers, are studied using first-principles methods. Such compounds are representative of a possible new class of materials in which ferroelectricity is perturbed by compositional breaking of inversion symmetry. For isovalent substitution the ferroelectric double-well potential becomes asymmetric, so that minority domains may no longer survive. The symmetry breaking is enormously stronger for heterovalent substitution; here the double-well behavior is destroyed. Tuning between these behaviors may allow for the optimization of desired materials properties.
对形式为(A(1/3)A(')(1/3)A(")(1/3))BO3和A(B(1/3)B(')(1/3)B(")(1/3))O3的立方钙钛矿化合物进行了第一性原理方法研究，其中不同的阳离子形成交替的单层系列。这类化合物代表了一类可能的新型材料，其中铁电性因反演对称性的成分破坏而受到扰动。对于等价取代，铁电双阱势变得不对称，因此少数畴可能不再存在。对于异价取代，对称性破坏要强得多；在这里，双阱行为被破坏。在这些行为之间进行调节可能允许优化所需的材料性能。
