Direct insight into the structure-property relation of interfaces from constrained crystal structure prediction

Abstract

A major issue that prevents a full understanding of heterogeneous materials is the lack of systematic first-principles methods to consistently predict energetics and electronic properties of reconstructed interfaces. In this work we address this problem with an efficient and accurate computational scheme. We extend the minima-hopping method implementing constraints crafted for two-dimensional atomic relaxation and enabling variations of the atomic density close to the interface. A combination of density-functional and accurate density-functional tight-binding calculations supply energy and forces to structure prediction. We demonstrate the power of this method by applying it to extract structure-property relations for a large and varied family of symmetric and asymmetric tilt boundaries in polycrystalline silicon. We find a rich polymorphism in the interface reconstructions, with recurring bonding patterns that we classify in increasing energetic order. Finally, a clear relation between bonding patterns and electrically active grain boundary states is unveiled and discussed.

Prediction and Characterization of Graphitic Structures at Diamond Grain Boundaries

“…In this approach, the adiabatic potential energy surface is explored by iteratively performing consecutive short molecular dynamics steps to escape from local minima, followed by local geometry relaxations that take into account both atomic and cell variables. The predictive power of this approach was already demonstrated in a wide variety of systems, ranging from bulk crystals to low-density structures, crystals with defects, ,, quasi two-dimensional materials, − and more. In particular, combining the MHM with adequate constraints, we have studied recently the geometrical reconstruction of internal interfaces in silicon and revealed the relation between recurrent bonding patterns and electronic properties at grain boundaries …”

“…The predictive power of this approach was already demonstrated in a wide variety of systems, ranging from bulk crystals to low-density structures, crystals with defects, ,, quasi two-dimensional materials, − and more. In particular, combining the MHM with adequate constraints, we have studied recently the geometrical reconstruction of internal interfaces in silicon and revealed the relation between recurrent bonding patterns and electronic properties at grain boundaries …”

“…The initial challenge of any computational study of complex interfaces is to reliably predict the atomic structure. In previous studies in the literature, diamond–graphene structures were either constructed from classical molecular dynamics ,, or inferred directly from high-resolution experimental images. ,,, Although such an approach leads to realistic models for the most symmetric interfaces, it limits considerably the reliability of more general reconstructions . Recently, we proposed a constrained crystal-structure prediction method capable of predicting in an efficient way internal reconstructions that minimize the interface energy .…”

“…In previous studies in the literature, diamond–graphene structures were either constructed from classical molecular dynamics ,, or inferred directly from high-resolution experimental images. ,,, Although such an approach leads to realistic models for the most symmetric interfaces, it limits considerably the reliability of more general reconstructions . Recently, we proposed a constrained crystal-structure prediction method capable of predicting in an efficient way internal reconstructions that minimize the interface energy . In the present work we rely on this approach, based on the minima hopping method and on a combination of density functional theory (DFT) and DFT tight-binding (DFTB) to provide energies and forces.…”

A Review on Phonon Transport within Polycrystalline Materials

“…More discussions on the GB structures can be found elsewhere. [140,141] Figure 8 summarizes the twist-angle-dependent thermal resistance of measured interfaces. Particular attention should be paid to the strong correlation between 𝑅 𝐾 and the strain part γ strain of the total GB energy 𝛾 𝐺𝐵 = 𝛾 𝑠𝑡𝑟𝑎𝑖𝑛 + 𝛾 𝑐𝑜𝑟𝑒 .…”