The collective dipole behaviors in (BaTiO3) m /(SrTiO3) n composite nanowires are investigated based on the first-principles-derived simulations. It demonstrates that such nanowire systems exhibit intriguing dipole orders, due to the combining effect of the anisotropic electrostatic interaction of the nanowire, the SrTiO3-layer-modified electrostatic interaction and the multiphase ground state of BaTiO3 layer. Particularly, a strong polar-toroidal coupling that is tunable by the SrTiO3-layer thickness, temperature, external strains and electric fields is found to exist in the nanowires, with the appearance of fruitful dipole states (including those being purely polar, purely toroidal, both polar and toroidal, or distorted toroidal) and phase boundaries. As a consequence, an efficient cross control of the toroidal (polar) order by static (curled) electric field, and superior piezoelectric and piezotoroidal responses, can be achieved in the nanowires. The result provides new insights into the collective dipole behaviors in nanowire systems.
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机译：基于（BaTiO 3 ） m /（SrTiO 3 ） n 复合纳米线研究了集体偶极子行为。第一原理派生的模拟。结果表明，由于纳米线的各向异性静电相互作用，SrTiO 3 层修饰的静电相互作用以及BaTiO 3 层。特别是，发现纳米线中存在可通过SrTiO 3 层的厚度，温度，外部应变和电场调节的强极性-环形耦合，并呈现出富有成效的偶极态（包括那些是纯极性，纯环形，极性和环形，或扭曲的环形）和相位边界。结果，可以在纳米线中实现通过静电（弯曲）电场对环形（极性）阶的有效交叉控制，以及出色的压电和压电环形响应。结果为纳米线系统中的集体偶极子行为提供了新的见解。
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