Tao Xu

Diamond nanoparticles synthesized by the detonation of explosives were used as an additive in paraffin oil. The tribological properties of the two-phase lubricant of paraffin oil and diamond nanoparticles were investigated. The results show that, under boundary lubricating conditions, this kind of two-phase lubricant possesses excellent load-carrying capacity, anti-wear and friction-reduction properties. The ball-bearing effect of diamond nanoparticles existed between the rubbing faces, the surf

Atomically thin multiferroics with the coexistence and cross-coupling of ferroelectric and (anti)ferromagnetic order parameters are promising for novel magnetoelectric nanodevices. However, such ferroic order disappears at a critical thickness in nanoscale. Here, we show a potential path toward ultrathin multiferroics by engineering an unusual domain wall (DW)-oxygen vacancy interaction in nonmagnetic ferroelectric PbTiO3. We demonstrate from first-principles that oxygen vacancies formed at the

Abstract The quest for new 2D ferroelectric materials continues to arouse interest. Based on first‐principles calculations, here, 2D ferroelectric properties in lead chalcogenides PbXs (X = S, Se, and Te) with a thickness of two atomic layers via strain engineering is demonstrated. Although these materials are stable in a rocksalt‐type cubic structure and are intrinsically nonferroelectric materials, an appropriate mechanical strain can readily activate a paraelectric to ferroelectric phase tran

Polar metals characterized by the simultaneous coexistence of a polar structure and metallicity have been a long-sought goal due to the promise of novel electronic devices. Developing such materials at low dimensions remains challenging since both conducting electrons and reduced dimensions are supposed to quench the polar state. Here, based on first-principles calculations, we report the discovery of a non-centrosymmetric polar structure in two-dimensional (2D) metallic materials with electrost

Polar topological structures such as skyrmions and merons have become an emerging research field due to their rich functionalities and promising applications in information storage. Up to now, the obtained polar topological structures are restricted to a few limited ferroelectrics with complex heterostructures, limiting their large-scale practical applications. Here, we circumvent this limitation by utilizing a nanoscale ripple-generated flexoelectric field as a universal means to create rich po

Abstract The coexistence of ferroelectricity, conductivity, and magnetism in a single-phase material has attracted considerable attention due to fundamental interest and tremendous technological potential. However, their mutually exclusive mechanisms hinder the discovery of multifunctional conducting multiferroics. Here, we propose a new material design approach for electron engineering to enable these conflicting properties to coexist. We use first principles calculations to demonstrate that ap

Topological objects with skyrmionic textures in ferroelectrics, i.e., polar skyrmions, are promising technological paradigms in next-generation electronic devices. While breakthrough discoveries of stable polar skyrmions approximately ten nanometers in size have been very recently witnessed in complex systems, such a nontrivial topological order in ferroelectrics inevitably disappears below the ferroelectric critical size of several nanometers. Herein, we propose a strategy to overcome this limi