Ferroelectric domain walls differ in their electrical conductivity under different electric and elastic boundary conditions, and this performance can be used to design memories. A phase-field model is developed to explore the effect of elastic, temperature, and toroidal electric fields on the electrical conductivity for a prototype domain-wall memory unit embedded in a center-type quadrant topological domain structure. It shows that the toroidal electric field can switch two states of the domain wall with high and low conductivity repeatedly, and the conductivity can be tuned by the temperature, misfit strain, and thickness. This work might provide significant reference and technical guidance for the design and application of ferroelectric-domain-wall memory.

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In order to achieve sustainable development goals, China has further increased its goal of reducing carbon intensity and has made digitalization an important support for sustainable development. However, the impact of digitalization on carbon intensity reduction is still unclear. In this context, this paper first evaluates the digitalization level of 30 provincial regions in China and then constructs a spatial Durbin model for two stages, 2012–2015 and 2016–2019, so as to explore the spatial spillover effects of carbon intensity in different stages and the important roles of digital infrastructure and digital inputs in carbon intensity reduction. The main findings are as follows: (1) the current digitization level of each province in China is widely disparate, with the region showing a high level in the east and a low level in the west; (2) carbon intensity reduction has a significant spatial spillover effect, as shown by a 1% reduction in local carbon intensity and a 0.21% reduction in neighboring regions; and (3) digitalization has a more significant positive impact on the reduction in carbon intensity in stage 2. The research results are strong demonstration that digitalization drives sustainable development.