Related papers: Transversal flexoelectric coefficients for fifty s…
Two-dimensional ferroelectric materials are beneficial for power-efficient memory devices and transistor applications. Here, we predict out-of-plane ferroelectricity in a new family of buckled metal oxide (MO; M: Ge, Sn, Pb) monolayers with…
Van der Waals (vdW) materials have greatly expanded our design space of heterostructures by allowing individual layers to be stacked at non-equilibrium configurations, for example via control of the twist angle. Such heterostructures not…
Layered materials with non-centrosymmetric stacking order are attracting increasing interest due to the presence of ferroelectric polarization, which is dictated by weak interlayer hybridization of atomic orbitals. Here, we use density…
We develop a general and unified first-principles theory of piezoelectric and flexoelectric tensor, formulated in such a way that the tensor elements can be computed directly in the context of density-functional calculations, including…
Non-conductive materials like rubbers, plastics, ceramics, and even semiconductors have the property of flexoelectricity, which means that they can generate electricity when bent and twisted. However, an irregular shape or a peculiar load…
We analyze the dielectric-function spectra of low dimensional transition metal dichalcogenides (TMDCs) using a fully analytical model of the complex dielectric function that is applicable in fractional dimensional space. We extract the…
In this work we use first-principles density-functional theory (DFT) calculations combined with the maximally localized Wannier function tight binding Hamiltonian (MLWF-TB) and Bethe-Salpeter equation (BSE) formalism to investigate…
We reveal that strong flexoelectric effect of solids can be induced due to the signfi?cant charge migration along the strain gradient direction, which represents a new understanding of the origin of flexoelectricity. Beyond the linear…
The flexoelectric behaviors of solids under high strain gradient can be distinct from that under low strain gradient. Using the generalized Bloch theorem, we investigate theoretically the transversal flexoelectric effects in bent MgO…
Layered transition metal dichalcogenides (TMDs) offer many attractive features for next-generation low-dimensional device geometries. Due to the practical and fabrication challenges related to in situ methods, the atomistic dynamics that…
The discovery of two-dimensional (2D) materials possessing switchable spontaneous polarization with atomic thickness opens up exciting opportunities to realize ultrathin, high-density electronic devices with potential applications ranging…
First-principle calculations with different exchange-correlation functionals, including LDA, PBE and vdW-DF functional in form of optB88-vdW, have been performed to investigate the electronic and elastic properties of two dimensional…
Symmetry breaking at surfaces and interfaces and the capability to support large strain gradients in nanoscale systems enable new forms of electromechanical coupling. Here we introduce the concept of quantum flexoelectricity, a phenomenon…
The electronic and thermoelectric properties of one to four monolayers of MoS$_{2}$, MoSe$_{2}$, WS$_{2}$, and WSe$_{2}$ are calculated. For few layer thicknesses,the near degeneracies of the conduction band $K$ and $\Sigma$ valleys and the…
We report a determination of the complex in-plane dielectric function of monolayers of four transition metal dichalcogenides: MoS2, MoSe2, WS2 and WSe2, for photon energies from 1.5 - 3 eV. The results were obtained from reflection spectra…
Two-dimensional materials with ferroelectric properties break the size effect of conventional ferroelectric materials and unlock unprecedented potentials of ferroelectric-related application at small length scales. In this work, using…
We elucidate the flexoelectricity of materials in the high strain gradient regime, of which the underlying mechanism is less understood. By using the generalized Bloch theorem, we uncover a strong flexoelectric-like effect in bent thinfilms…
We propose an analytical approach for calculating the linear and nonlinear optical (NLO) responses of monolayer transition metal dichalcogenides (TMDs) including excitonic effects. An effective Hamiltonian reproducing the trigonal warping…
We carry out a systematic study of the thermal conductivity of four single-layer transition metal dichalcogenides, MX$_2$ (M = Mo, W; X = S, Se) from first-principles by solving the Boltzmann Transport Equation (BTE). We compare three…
The structural, dynamical, and thermodynamical properties of diamond, graphite and layered derivatives (graphene, rhombohedral graphite) are computed using a combination of density-functional theory (DFT) total-energy calculations and…