Superconductivity in Shear Strained Semiconductors

Abstract

Semiconductivity and superconductivity are remarkable quantum phenomena that have immense impact on science and technology, and materials that can be tuned, usually by pressure or doping, to host both types of quantum states are of great fundamental and practical significance. Here we show by first-principles calculations a distinct route for tuning semiconductors into superconductors by diverse large-range elastic shear strains, as demonstrated in exemplary cases of silicon and silicon carbide. Analysis of strain driven evolution of bonding structure, electronic states, lattice vibration, and electron-phonon coupling unveils robust pervading deformation induced mechanisms auspicious for modulating semiconducting and superconducting states under versatile material conditions. This finding opens vast untapped structural configurations for rational exploration of tunable emergence and transition of these intricate quantum phenomena in a broad range of materials.

Robust Nonmetallicity of NH3BH3 under Extreme Deviatoric Stresses

“…Such nonhydrostatic stresses are capable of driving distinct structural and property changes in the sample, leading to unexpected material behaviors. Pertinent examples include stress-induced ductile flow, metallization and superconductivity of normally superhard, brittle, and electrically insulating diamond, , stress-driven metallization and superconductivity of semiconductors silicon and silicon carbide, stress-modulated superconductivity in superhydride H 3 S, and stress-promoted electronic bandgap closure and resulting metallization of solid molecular hydrogen at reduced pressures compared to the hydrostatic case . These results showcase the prominent role of nonhydrostatic stresses in generating structural forms and physical properties not seen under hydrostatic conditions; consequently, materials research under extreme compression to ultrahigh megabar pressures needs to consider the influence of such deviatoric stresses beyond the hydrostatic description and examine their effects on physical properties.…”

Unexpected Strength of Noble Gas Solids in Diamond Anvil Cells

“…Elastic constants were calculated using the strain–stress method, and elastic moduli were derived from the Voigt-Reuss-Hill averaging scheme. Stress–strain relations under shear and compressive loading conditions were determined using the well-developed method. − At each step, a fixed strain was applied with a strain increment of 0.01, and the corresponding stress was determined. Moreover, the other five components of the Hellmann–Feynman stress tensors and atoms inside the unit cell were simultaneously relaxed until the residual forces and stresses were less than 0.005 eV/Å and 0.1 GPa, respectively.…”

Structural and Stress Response of Nanotwinned B13CN under Large Strains

“…The chemical bonding properties were quantitatively described with the Crystal orbital Hamilton populations (COHPs) as implemented in the LOBSTER program . The quasistatic ideal strength and relaxed loading path were determined using the established stress–strain method − in which the lattice vectors were incrementally deformed along the direction of the applied (tensile or shear) strains. At each step, the applied (tensile or shear) strain was fixed to determine the tensile or shear stress, while the other five independent components of the strain tensors as well as all the atoms inside the unit cell were simultaneously relaxed until (i) all the residual components of the Hellmann–Feynman stress tensor that were orthogonal to the applied strain were <0.1 GPa and (ii) the force on each atom became negligible.…”