High-throughput density functional calculations of solids are highly time-consuming. As an alternative, we propose a machine learning approach for the fast prediction solid-state properties. To achieve this, local spin-density approximation used as training set. We focus on predicting value electronic states at Fermi energy. find that conventional representations input data, such Coulomb matrix, not suitable machines in case periodic solids. novel crystal structure representation which and...

Two hydrogen-rich materials, H$_3$S and LaH$_{10}$, synthesized at megabar pressures, have revolutionized the field of condensed matter physics providing first glimpse to solution hundred-year-old problem room temperature superconductivity. The mechanism underlying superconductivity in these exceptional compounds is conventional electron-phonon coupling. Here we describe recent advances experimental techniques, theory first-principles computational methods which made possible discoveries....

Abstract The primary challenge in the field of high-temperature superconductivity hydrides is to achieve a superconducting state at ambient pressure rather than extreme pressures that have been required experiments so far. Here, we propose family compounds, composition Mg 2 XH 6 with X = Rh, Ir, Pd, or Pt, achieves this goal. These materials were identified by scrutinizing more million compounds using machine-learning accelerated high-throughput workflow. We predict their transition...

Abstract A machine‐learning‐assisted approach is employed to search for superconducting hydrides under ambient pressure within an extensive dataset comprising over 150 000 compounds. The investigation yields ≈50 systems with transition temperatures surpassing 20 K, and some even reaching above 70 K. These compounds have very different crystal structures, dimensionality, chemical composition, stoichiometry, arrangement of the hydrogens. Interestingly, most these display slight thermodynamic...

We present a first-principles study of the electron-phonon interaction and prediction superconducting critical temperature in molecular metallic hydrogen. Our is able to single out features which drive system towards superconductivity: mainly, rich complex Fermi surface strongly coupled phonon modes driving intra- or intermolecular charge transfer. demonstrate that this simple system, very high can be reached via Coulomb electron-electron interactions.

A new parameter-free approximation for the exchange-correlation kernel ${f}_{\mathrm{xc}}$ of time-dependent density-functional theory is proposed. This expressed as an algorithm in which exact Dyson equation response, well approximate expression terms dielectric function, are solved together self-consistently, leading to a simple kernel. We apply this calculation optical spectra various small band gap (Ge, Si, GaAs, AlN, ${\mathrm{TiO}}_{2}$, SiC), large (C, LiF, Ar, Ne), and magnetic (NiO)...

Extreme pressure strongly affects the superconducting properties of "simple" elemental metals, such as Li, K, and Al. Pressure induces superconductivity in Li (as high 17 K) while suppressing it We report first-principles investigations dense Al based on a recently proposed, parameter-free, method. Our results show an unprecedented agreement with experiments, assess predictive power method over wide range densities electron-phonon couplings, provide predictions for where no experiments exist...

Reports on sulfur hydride attaining metallicity under pressure and exhibiting superconductivity at temperatures as high 200 K have spurred an intense search for another room-temperature superconductor among hydrogen-rich compounds. Recently, compressed phosphorus (phosphine) was reported to metallize pressures above 45 GPa, reaching a superconducting transition temperature (${T}_{c}$) of 100 GPa. However, neither the exact composition nor crystal structure phase been conclusively determined....

Due to its low atomic mass hydrogen is the most promising element search for high-temperature phononic superconductors. However, metallic phases of are only expected at extreme pressures (400 GPa or higher). The measurement a record superconducting critical temperature 190 K in hydrogen-sulfur compound 200 pressure[1], shows that metallization can be reached significantly lower pressure by inserting it matrix other elements. In this work we re-investigate phase diagram and properties H-S...

We present an application of Eliashberg theory superconductivity to study a set novel superconducting systems with wide range structural and chemical properties. The includes three intercalated group-IV honeycomb layered structures, SH3 at 200 GPa (the superconductor the highest measured critical temperature), similar system SeH3 150 GPa, lithium doped mono-layer black phosphorus. theoretical approach we adopt is recently developed, fully ab initio that takes into account Coulomb interaction...

A large scale study of conventional superconducting materials using a machine-learning accelerated high-throughput workflow is performed, starting by creating comprehensive dataset around 7000 electron-phonon calculations performed with reasonable convergence parameters. This then used to train robust machine learning model capable predicting the and properties based on structural, compositional, electronic ground-state properties. Using this machine, transition temperatures (T

We report first-principles calculations of the superconducting properties ${\mathrm{CaC}}_{6}$, obtained within density functional theory superconductivity. find a moderately anisotropic gap which is larger on Fermi surface sheet with interlayer and Ca character compared isotropic calculations. Our calculated anisotropy improves agreement specific heat experiments consistent recent tunneling experiments. In contrast to ${\mathrm{MgB}}_{2}$, we do not multigap superconductivity but, instead,...

Density-functional theory (DFT) for electrons at finite temperature is increasingly important in condensed matter and chemistry. The exact conditions that have proven crucial constraining constructing accurate approximations ground-state DFT are generalized to temperature, including the adiabatic connection formula. We discuss consequences functional construction.

Starting from the experimental data contained in inorganic crystal structure database, we use a statistical analysis to determine likelihood that chemical element A can be replaced by another B given structure. This information used construct matrix where each entry is measure of this likelihood. By ordering rows and columns order reduce its bandwidth, one-dimension elements, analogous famous Pettifor scale. The new scale shows large similarities with one Pettifor, but also striking...

Among elemental compounds, the high-pressure superconducting phase diagram of phosphorus is one most complex. Resistivity measurements and $a\phantom{\rule{0}{0ex}}b$ $i\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}o$ superconductivity calculations reported in this paper solve for first time open controversies on anomalous trends; forming a single, consistent scenario multiple metastable structures which coexist beyond...

We propose a practical alternative to Eliashberg equations for the ab initio calculation of superconducting transition temperatures and gap functions. Within recent density functional theory superconductors, we develop an exchange-correlation that retains accuracy Migdal's approximation many-body electron-phonon self-energy, while having simple analytic form. Our is based on parametrization self-energy superconductor with single Einstein frequency, enables calculations experimental...

${\text{BaBiO}}_{3}$ is characterized by a charge disproportionation with half of the Bi atoms possessing valence $3+$ and $5+$. Because self-interaction errors, local- semilocal-density functionals fail to describe quantitatively, yielding too small structural distortion no band gap. Using hybrid functionals, we obtain satisfactory description structural, electronic, optical, vibrational properties ${\text{BaBiO}}_{3}$. The results obtained using GW (Green's function G screened Coulomb...

We perform first-principles calculations of the band and $\mathbit{k}$-point resolved superconducting gap Pb in framework density functional theory for superconductors. Without any adjustable parameter or assuption different from $s$-wave symmetry, we find two values on sheets Fermi surface, which can be related to electron-phonon couplings characterizing electronic states corresponding bands. These, turn, derive orbital character states. also some intraband anisotropy each surface sheet....

A detailed study of the electron-phonon interaction in $Cmca$ phase metallic hydrogen and its implications superconducting properties is presented. careful analysis role played by anisotropy presence multigaps allows to single out peculiarities that drive superconductivity at very high temperature this system.

Samples of few-layer phosphorene can be produced by mechanical or liquid exfoliation. However, it remains challenging to produce flakes with large sizes. Optical spectroscopy performed on has revealed a peculiar gap dependence that is roughly inversely proportional the layer number. This been poorly understood date. Because their small size, these samples have out reach powerful electronic structure characterization techniques such as angle-resolved photoemission (ARPES). The present work...

Abstract We present a scanning tunneling microscopy (STM) and ab-initio study of the anisotropic superconductivity 2H-NbSe 2 in charge-density-wave (CDW) phase. Differential-conductance spectra show clear double-peak structure, which is well reproduced by density functional theory simulations enabling full k - real-space resolution superconducting gap. The hollow-centered (HC) chalcogen-centered (CC) CDW patterns observed experiment are mapped onto separate van der Waals layers with...