Related papers: Modeling polar order in compressively strained SrT…
We develop a theory of superconducting pairing in low-density Strontium titanate due to quadratic coupling of electron density to soft transverse optical phonons. It leads to static attractive potential between electrons which decay length…
Metallic strontium titanate (SrTiO$_3$) is known to have both normal-state and superconducting properties that vary strongly over a wide range of charge carrier densities. This indicates the importance of nonlinear dynamics, and has…
The superconducting order parameter of strontium ruthenate is the center of a lasting puzzle calling for theoretical studies that include the seldom-considered effects of spin-orbit coupling and the frequency-dependence of the order…
Superconducting domes, ubiquitous across a variety of quantum materials, are often understood as a window favorite for pairing opened by the fluctuations of competing orders. Yet, a quantitative understanding of how such a window closes is…
SrTiO$_{3}$ undergoes a cubic-to-tetragonal phase transition at 105K. This antiferrodistortive transition is believed to be in competition with incipient ferroelectricity. Substituting strontium by isovalent calcium induces a ferroelectric…
SrTiO$_{3}$, a quantum paraelectric, becomes a metal with a superconducting instability after removal of an extremely small number of oxygen atoms. It turns into a ferroelectric upon substitution of a tiny fraction of strontium atoms with…
Multiferroicity can be induced in strontium titanate by applying biaxial strain, resulting in the coexistence of both ferroelectric and antiferrodistortive domains. The magnitude and sign of the strain imposed on the lattice by design can…
A spin-orbital superexchange Hamiltonian in a Mott insulator with $t_{2g}$ orbital degeneracy is investigated. More specifically, we focus on a spin ferromagnetic state of the model and study a collective behavior of orbital angular…
Doped strontium titanate SrTiO$_3$ (STO) is one of the most dilute superconductors known today. The fact that superconductivity occurs at very low carrier concentrations is one of the two reasons that the pairing mechanism is not yet…
Ferroelectrics show a phase transition to a paraelectric phase at a well-defined transition temperature. Introducing disorder makes this transition diffuse, and the system becomes a relaxor. Since the degree of (dis-)order is usually…
The properties of quantum materials are commonly tuned using experimental variables such as pressure, magnetic field and doping. Here we explore a different approach: irreversible, plastic deformation of single crystals. We show for the…
Electric double layer transistor configurations have been employed to electrostatically dope single crystals of insulating SrTiO_{3}. Here we report on the results of such doping over broad ranges of temperature and carrier concentration…
We use density-functional theory with the local-density approximation to study the structural and ferroelectric properties of SrTiO$_3$ under misfit strains. Both the antiferrodistortive (AFD) and ferroelectric (FE) instabilities are…
Monodispersed strontium titanate nanoparticles were prepared and studied in detail. It is found that ~10 nm as-prepared stoichiometric nanoparticles are in a polar structural state (with possibly ferroelectric properties) over a broad…
The first switchable electric polarization in metals was recently discovered in bilayer and trilayer WTe2. Strangely, despite the tininess of the ordered polarization, the ferroelectricity survives up to 350 K, rendering the mechanism of…
The ferroelectric phase transition in barium titanate under pressure was studied within the framework of Landau-Ginzburg theory using differential scanning calorimetry. An innovative method for high-sensitive thermal measurements under…
Achieving electrostatic control of quantum phases is at the frontier of condensed matter research. Recent investigations have revealed superconductivity tunable by electrostatic doping in twisted graphene heterostructures and in…
Understanding ferroelectricity is of both fundamental and technological importance to further stimulate the development of new materials designs and manipulations. Here, we perform an in-depth first-principle study on the well-known…
In this paper, an efficient computational material design approach (cluster expansion) is employed for the ferroelectric $PbTiO_3$/$SrTiO_3$ system. Via exploring a conguration space including over $3 \times 10^6$ candidates, two special…
Doped strontium titanate becomes superconducting at a density as low as n = 5 x 10^17 cm^-3, where the Fermi energy is orders of magnitude smaller than the longitudinal-optical-phonon frequencies. In this limit the only optical mode with a…