Gian-marco Rignanese - Profile on Academia.edu (original) (raw)

Papers by Gian-marco Rignanese

Are Protons Involve in the Fading Capacity in Li Ion Aqueous Batteries? Shedding Light By Means of First Principle Computations

ECS Meeting Abstracts

Li diffusion in Si and LiSi: Nuclear quantum effects and anharmonicity

The Journal of Chemical Physics

Computer Physics Communications

Ab initio many-body perturbation theory within the GW approximation is a Green's function formali... more Ab initio many-body perturbation theory within the GW approximation is a Green's function formalism widely used in the calculation of quasiparticle excitation energies of solids. In what has become an increasingly standard approach, Kohn-Sham eigenenergies, generated from a DFT calculation with a strategically-chosen exchange correlation functional "starting point", are used to construct G and W , and then perturbatively corrected by the resultant GW self-energy. In practice, there are several ways to construct the GW self-energy, and these can lead to variations in predicted quasiparticle energies. For example, for ZnO and TiO2, reported GW fundamental gaps can vary by more than 1 eV. In this work, we address the convergence and key approximations in contemporary G0W0 calculations, including frequency-integration schemes and the treatment of the Coulomb divergence in the exact-exchange term. We study several systems, and compare three different GW codes: BerkeleyGW, Abinit and Yambo. We demonstrate, for the first time, that the same quasiparticle energies for systems in the condensed phase can be obtained with different codes, and we provide a comprehensive assessment of implementations of the GW approximation. arXiv:1903.06865v1 [cond-mat.mtrl-sci]

npj Computational Materials

The colours of metals have attracted the attention of humanity since ancient times, and coloured ... more The colours of metals have attracted the attention of humanity since ancient times, and coloured metals, in particular gold compounds, have been employed for tools and objects symbolizing the aesthetics of power. In this work, we develop a comprehensive framework to obtain the reflectivity and colour of metals, and show that the trends in optical properties and the colours can be predicted by straightforward first-principles techniques based on standard approximations. We apply this to predict reflectivity and colour of several elemental metals and of different types of metallic compounds (intermetallics, solid solutions and heterogeneous alloys), considering mainly binary alloys based on noble metals. We validate the numerical approach through an extensive comparison with experimental data and the photorealistic rendering of known coloured metals.

The Abinitproject: Impact, environment and recent developments

Computer Physics Communications

Effect of Cd on cation redistribution and order-disorder transition in Cu2(Zn,Cd)SnS4

Journal of Materials Chemistry A

Cation substitution has been extensively used to improve the fundamental optoelectronic propertie... more Cation substitution has been extensively used to improve the fundamental optoelectronic properties and the photovoltaic performance of kesterite solar cells, and some of the most promising results have been obtained...

The Pauling rules have served to analyze and rationalize crystal structures for decades. So far, ... more The Pauling rules have served to analyze and rationalize crystal structures for decades. So far, there is no statistical answer on how these five rules perform. Here, we show the analysis of all five Pauling rules based on the geometrical data of around 5000 oxides. To do this, we determined the coordination environments of all 5000 oxides and compared our geometrical analysis to the prediction of the Pauling rules. We arrived at the conclusion that the Pauling rules - especially the electrostatic valence principle - perform poorly for most of the oxides: only 13% of all oxides simultaneously satisfy rules from two to five. To arrive at such an intuitive understanding of the stability of crystals that Pauling’s rules gave shortly after their development again, we should develop new and improved rules.

npj Computational Materials

Materials combining strong ferromagnetism and good semiconducting properties are highly desirable... more Materials combining strong ferromagnetism and good semiconducting properties are highly desirable for spintronic applications (e.g., in spin-filtering devices). In this work, we conduct a search for concentrated ferromagnetic semiconductors through highthroughput computational screening. Our screening reveals the limited availability of semiconductors combining ferromagnetism and a low effective mass. We identify the manganese pyrochlore oxide In 2 Mn 2 O 7 as especially promising for spin transport as it combines low electron effective mass (0.29 m 0 ), a large exchange splitting of the conduction band (1.1 eV), stability in air, and a Curie temperature (about 130 K) among the highest of concentrated ferromagnetic semiconductors. We rationalise the high performance of In 2 Mn 2 O 7 by the unique combination of a pyrochlore lattice favouring ferromagnetism with an adequate alignment of O-2p, Mn-3d, and In-5s forming a dispersive conduction band while enhancing the Curie temperature.

Computational Materials Science

The diffusion of large databases collecting different kind of material properties from highthroug... more The diffusion of large databases collecting different kind of material properties from highthroughput density functional theory calculations has opened new paths in the study of materials science thanks to data mining and machine learning techniques. Phonon calculations have already been employed successfully to predict materials properties and interpret experimental data, e.g. phase stability, ferroelectricity and Raman spectra, so their availability for a large set of materials will further increase the analytical and predictive power at hand. Moving to a larger scale with density functional perturbation calculations, however, requires the presence of a robust framework to handle this challenging task. In light of this, we automatized the phonon calculation and applied the result to the analysis of the convergence trends for several materials. This allowed to identify and tackle some common problems emerging in this kind of simulations and to lay out the basis to obtain reliable phonon band structures from high-throughput calculations, as well as optimizing the approach to standard phonon simulations. arXiv:1710.06028v2 [cond-mat.mtrl-sci]

npj Computational Materials

Transparent conducting materials (TCMs) are required in many applications from solar cells to tra... more Transparent conducting materials (TCMs) are required in many applications from solar cells to transparent electronics. Developing high performance materials combining the antagonistic properties of transparency and conductivity has been challenging especially for p-type materials. Recently, high-throughput ab initio computational screening has emerged as a formidable tool for accelerating materials discovery. In this review, we discuss how this approach has been applied for identifying TCMs. We provide a brief overview of the different materials properties of importance for TCMs (e.g., dopability, effective mass, and transparency) and present the ab initio techniques available to assess them. We focus on the accuracy of the methodologies as well as their suitability for high-throughput computing. Finally, we review the different high-throughput computational studies searching for new TCMs and discuss their differences in terms of methodologies and main findings.

Journal of Materials Chemistry C

Metal phosphides are predicted to have high thermoelectric performance due to enhanced electronic... more Metal phosphides are predicted to have high thermoelectric performance due to enhanced electronic band structures and low thermal conductivities.

Journal of Materials Chemistry A

Engineering the thermal properties in solids is important for both fundamental physics (e.g., ele... more Engineering the thermal properties in solids is important for both fundamental physics (e.g., electric and phonon transport) and device applications (e.g., thermal insulating coating, thermoelectrics). In this paper, we report...

Physical Review Materials

We present a general scheme of range-separated hybrid functionals in which the mixing parameters ... more We present a general scheme of range-separated hybrid functionals in which the mixing parameters of Fock exchange are fully nonempirical and determined solely from the dielectric function. We show that the full dielectric dependence leads to an unscreened Fock exchange in the short range, while in the long range the Fock exchange is correctly screened by the macroscopic dielectric constant. The range separation is obtained by fitting to the calculated static dielectric function in the long-wavelength limit. The resulting hybrid functional accurately accounts for electronic and structural properties of various semiconductors and insulators spanning a wide range of band gaps.

Tuning Optical Properties of Dibenzochrysenes by Functionalization: A Many-Body Perturbation Theory Study

The Journal of Physical Chemistry C

Joule

In the design of materials with low lattice thermal conductivity, compounds with high density, lo... more In the design of materials with low lattice thermal conductivity, compounds with high density, low speed of sound, and complexity at either the atomic, nano-or microstructural level are preferred. The layered compound Mg 3 Sb 2 defies these prevailing paradigms, exhibiting lattice thermal conductivity comparable to PbTe and Bi 2 Te 3 , despite its low density and simple structure. The excellent thermoelectric performance (zT ∼ 1.5) in n-type Mg 3 Sb 2 has thus far been attributed to its multi-valley conduction band, while its anomalous thermal properties have been largely overlooked. To explain the origin of the low lattice thermal conductivity of Mg 3 Sb 2 , we have used both experimental methods and ab initio phonon calculations to investigate trends in the elasticity, thermal expansion and anharmonicity of AMg 2 Pn 2 Zintl compounds with A = Mg, Ca, Yb, and Pn = Sb and Bi. Phonon calculations within the quasiharmonic approximation reveal large mode Grüneisen parameters in Mg 3 Sb 2 compared with isostructural compounds, in particular in transverse acoustic modes involving shearing of adjacent anionic layers. Measurements of the elastic moduli and sound velocity as a function of temperature using resonant ultrasound spectroscopy provide a window into the softening of the acoustic branches at high temperature, confirming their exceptionally high anharmonicity. We attribute the anomalous thermal behavior of Mg 3 Sb 2 to the diminutive size of Mg, which may be too small for the octahedrally-coordinated site, leading to weak, unstable interlayer Mg-Sb bonding. This suggests more broadly that soft shear modes resulting from undersized cations provide a potential route to achieving low lattice thermal conductivity low-density, earth-abundant materials.

Scientific data, 2018

The knowledge of the vibrational properties of a material is of key importance to understand phys... more The knowledge of the vibrational properties of a material is of key importance to understand physical phenomena such as thermal conductivity, superconductivity, and ferroelectricity among others. However, detailed experimental phonon spectra are available only for a limited number of materials, which hinders the large-scale analysis of vibrational properties and their derived quantities. In this work, we perform ab initio calculations of the full phonon dispersion and vibrational density of states for 1521 semiconductor compounds in the harmonic approximation based on density functional perturbation theory. The data is collected along with derived dielectric and thermodynamic properties. We present the procedure used to obtain the results, the details of the provided database and a validation based on the comparison with experimental data.

Van der Waals Interactions and Anharmonicity in the Lattice Vibrations, Dielectric Constants, Effective Charges, and Infrared Spectra of the Organic–Inorganic Halide Perovskite CH3NH3PbI3

The Journal of Physical Chemistry C

Scientific data, Jul 4, 2017

Electronic transport in materials is governed by a series of tensorial properties such as conduct... more Electronic transport in materials is governed by a series of tensorial properties such as conductivity, Seebeck coefficient, and effective mass. These quantities are paramount to the understanding of materials in many fields from thermoelectrics to electronics and photovoltaics. Transport properties can be calculated from a material's band structure using the Boltzmann transport theory framework. We present here the largest computational database of electronic transport properties based on a large set of 48,000 materials originating from the Materials Project database. Our results were obtained through the interpolation approach developed in the BoltzTraP software, assuming a constant relaxation time. We present the workflow to generate the data, the data validation procedure, and the database structure. Our aim is to target the large community of scientists developing materials selection strategies and performing studies involving transport properties.

J. Mater. Chem. C, 2017

We demonstrate through first principles computations how the metal–oxygen–metal angle directly dr... more We demonstrate through first principles computations how the metal–oxygen–metal angle directly drives the hole effective mass (thus the carrier mobility) in p-type s-orbital-based oxides.

Physical chemistry chemical physics : PCCP, Jan 17, 2017

Bournonite (CuPbSbS3) is an earth-abundant mineral with potential thermoelectric applications. Th... more Bournonite (CuPbSbS3) is an earth-abundant mineral with potential thermoelectric applications. This material has a complex crystal structure (space group Pmn21 #31) and has previously been measured to exhibit a very low thermal conductivity (κ < 1 W m(-1) K(-1) at T ≥ 300 K). In this study, we employ high-throughput density functional theory calculations to investigate how the properties of the bournonite crystal structure change with elemental substitutions. Specifically, we compute the stability and electronic properties of 320 structures generated via substitutions {Na-K-Cu-Ag}{Si-Ge-Sn-Pb}{N-P-As-Sb-Bi}{O-S-Se-Te} in the ABCD3 formula. We perform two types of transport calculations: the BoltzTraP model, which has been extensively tested, and a newer AMSET model that we have developed and which incorporates scattering effects. We discuss the differences in the model results, finding qualitative agreement except in the case of degenerate bands. Based on our calculations, we ide...

Are Protons Involve in the Fading Capacity in Li Ion Aqueous Batteries? Shedding Light By Means of First Principle Computations

ECS Meeting Abstracts

Li diffusion in Si and LiSi: Nuclear quantum effects and anharmonicity

The Journal of Chemical Physics

Computer Physics Communications

Ab initio many-body perturbation theory within the GW approximation is a Green's function formali... more Ab initio many-body perturbation theory within the GW approximation is a Green's function formalism widely used in the calculation of quasiparticle excitation energies of solids. In what has become an increasingly standard approach, Kohn-Sham eigenenergies, generated from a DFT calculation with a strategically-chosen exchange correlation functional "starting point", are used to construct G and W , and then perturbatively corrected by the resultant GW self-energy. In practice, there are several ways to construct the GW self-energy, and these can lead to variations in predicted quasiparticle energies. For example, for ZnO and TiO2, reported GW fundamental gaps can vary by more than 1 eV. In this work, we address the convergence and key approximations in contemporary G0W0 calculations, including frequency-integration schemes and the treatment of the Coulomb divergence in the exact-exchange term. We study several systems, and compare three different GW codes: BerkeleyGW, Abinit and Yambo. We demonstrate, for the first time, that the same quasiparticle energies for systems in the condensed phase can be obtained with different codes, and we provide a comprehensive assessment of implementations of the GW approximation. arXiv:1903.06865v1 [cond-mat.mtrl-sci]

npj Computational Materials

The colours of metals have attracted the attention of humanity since ancient times, and coloured ... more The colours of metals have attracted the attention of humanity since ancient times, and coloured metals, in particular gold compounds, have been employed for tools and objects symbolizing the aesthetics of power. In this work, we develop a comprehensive framework to obtain the reflectivity and colour of metals, and show that the trends in optical properties and the colours can be predicted by straightforward first-principles techniques based on standard approximations. We apply this to predict reflectivity and colour of several elemental metals and of different types of metallic compounds (intermetallics, solid solutions and heterogeneous alloys), considering mainly binary alloys based on noble metals. We validate the numerical approach through an extensive comparison with experimental data and the photorealistic rendering of known coloured metals.

The Abinitproject: Impact, environment and recent developments

Computer Physics Communications

Effect of Cd on cation redistribution and order-disorder transition in Cu2(Zn,Cd)SnS4

Journal of Materials Chemistry A

Cation substitution has been extensively used to improve the fundamental optoelectronic propertie... more Cation substitution has been extensively used to improve the fundamental optoelectronic properties and the photovoltaic performance of kesterite solar cells, and some of the most promising results have been obtained...

The Pauling rules have served to analyze and rationalize crystal structures for decades. So far, ... more The Pauling rules have served to analyze and rationalize crystal structures for decades. So far, there is no statistical answer on how these five rules perform. Here, we show the analysis of all five Pauling rules based on the geometrical data of around 5000 oxides. To do this, we determined the coordination environments of all 5000 oxides and compared our geometrical analysis to the prediction of the Pauling rules. We arrived at the conclusion that the Pauling rules - especially the electrostatic valence principle - perform poorly for most of the oxides: only 13% of all oxides simultaneously satisfy rules from two to five. To arrive at such an intuitive understanding of the stability of crystals that Pauling’s rules gave shortly after their development again, we should develop new and improved rules.

npj Computational Materials

Materials combining strong ferromagnetism and good semiconducting properties are highly desirable... more Materials combining strong ferromagnetism and good semiconducting properties are highly desirable for spintronic applications (e.g., in spin-filtering devices). In this work, we conduct a search for concentrated ferromagnetic semiconductors through highthroughput computational screening. Our screening reveals the limited availability of semiconductors combining ferromagnetism and a low effective mass. We identify the manganese pyrochlore oxide In 2 Mn 2 O 7 as especially promising for spin transport as it combines low electron effective mass (0.29 m 0 ), a large exchange splitting of the conduction band (1.1 eV), stability in air, and a Curie temperature (about 130 K) among the highest of concentrated ferromagnetic semiconductors. We rationalise the high performance of In 2 Mn 2 O 7 by the unique combination of a pyrochlore lattice favouring ferromagnetism with an adequate alignment of O-2p, Mn-3d, and In-5s forming a dispersive conduction band while enhancing the Curie temperature.

Computational Materials Science

The diffusion of large databases collecting different kind of material properties from highthroug... more The diffusion of large databases collecting different kind of material properties from highthroughput density functional theory calculations has opened new paths in the study of materials science thanks to data mining and machine learning techniques. Phonon calculations have already been employed successfully to predict materials properties and interpret experimental data, e.g. phase stability, ferroelectricity and Raman spectra, so their availability for a large set of materials will further increase the analytical and predictive power at hand. Moving to a larger scale with density functional perturbation calculations, however, requires the presence of a robust framework to handle this challenging task. In light of this, we automatized the phonon calculation and applied the result to the analysis of the convergence trends for several materials. This allowed to identify and tackle some common problems emerging in this kind of simulations and to lay out the basis to obtain reliable phonon band structures from high-throughput calculations, as well as optimizing the approach to standard phonon simulations. arXiv:1710.06028v2 [cond-mat.mtrl-sci]

npj Computational Materials

Transparent conducting materials (TCMs) are required in many applications from solar cells to tra... more Transparent conducting materials (TCMs) are required in many applications from solar cells to transparent electronics. Developing high performance materials combining the antagonistic properties of transparency and conductivity has been challenging especially for p-type materials. Recently, high-throughput ab initio computational screening has emerged as a formidable tool for accelerating materials discovery. In this review, we discuss how this approach has been applied for identifying TCMs. We provide a brief overview of the different materials properties of importance for TCMs (e.g., dopability, effective mass, and transparency) and present the ab initio techniques available to assess them. We focus on the accuracy of the methodologies as well as their suitability for high-throughput computing. Finally, we review the different high-throughput computational studies searching for new TCMs and discuss their differences in terms of methodologies and main findings.

Journal of Materials Chemistry C

Metal phosphides are predicted to have high thermoelectric performance due to enhanced electronic... more Metal phosphides are predicted to have high thermoelectric performance due to enhanced electronic band structures and low thermal conductivities.

Journal of Materials Chemistry A

Engineering the thermal properties in solids is important for both fundamental physics (e.g., ele... more Engineering the thermal properties in solids is important for both fundamental physics (e.g., electric and phonon transport) and device applications (e.g., thermal insulating coating, thermoelectrics). In this paper, we report...

Physical Review Materials

We present a general scheme of range-separated hybrid functionals in which the mixing parameters ... more We present a general scheme of range-separated hybrid functionals in which the mixing parameters of Fock exchange are fully nonempirical and determined solely from the dielectric function. We show that the full dielectric dependence leads to an unscreened Fock exchange in the short range, while in the long range the Fock exchange is correctly screened by the macroscopic dielectric constant. The range separation is obtained by fitting to the calculated static dielectric function in the long-wavelength limit. The resulting hybrid functional accurately accounts for electronic and structural properties of various semiconductors and insulators spanning a wide range of band gaps.

Tuning Optical Properties of Dibenzochrysenes by Functionalization: A Many-Body Perturbation Theory Study

The Journal of Physical Chemistry C

Joule

In the design of materials with low lattice thermal conductivity, compounds with high density, lo... more In the design of materials with low lattice thermal conductivity, compounds with high density, low speed of sound, and complexity at either the atomic, nano-or microstructural level are preferred. The layered compound Mg 3 Sb 2 defies these prevailing paradigms, exhibiting lattice thermal conductivity comparable to PbTe and Bi 2 Te 3 , despite its low density and simple structure. The excellent thermoelectric performance (zT ∼ 1.5) in n-type Mg 3 Sb 2 has thus far been attributed to its multi-valley conduction band, while its anomalous thermal properties have been largely overlooked. To explain the origin of the low lattice thermal conductivity of Mg 3 Sb 2 , we have used both experimental methods and ab initio phonon calculations to investigate trends in the elasticity, thermal expansion and anharmonicity of AMg 2 Pn 2 Zintl compounds with A = Mg, Ca, Yb, and Pn = Sb and Bi. Phonon calculations within the quasiharmonic approximation reveal large mode Grüneisen parameters in Mg 3 Sb 2 compared with isostructural compounds, in particular in transverse acoustic modes involving shearing of adjacent anionic layers. Measurements of the elastic moduli and sound velocity as a function of temperature using resonant ultrasound spectroscopy provide a window into the softening of the acoustic branches at high temperature, confirming their exceptionally high anharmonicity. We attribute the anomalous thermal behavior of Mg 3 Sb 2 to the diminutive size of Mg, which may be too small for the octahedrally-coordinated site, leading to weak, unstable interlayer Mg-Sb bonding. This suggests more broadly that soft shear modes resulting from undersized cations provide a potential route to achieving low lattice thermal conductivity low-density, earth-abundant materials.

Scientific data, 2018

The knowledge of the vibrational properties of a material is of key importance to understand phys... more The knowledge of the vibrational properties of a material is of key importance to understand physical phenomena such as thermal conductivity, superconductivity, and ferroelectricity among others. However, detailed experimental phonon spectra are available only for a limited number of materials, which hinders the large-scale analysis of vibrational properties and their derived quantities. In this work, we perform ab initio calculations of the full phonon dispersion and vibrational density of states for 1521 semiconductor compounds in the harmonic approximation based on density functional perturbation theory. The data is collected along with derived dielectric and thermodynamic properties. We present the procedure used to obtain the results, the details of the provided database and a validation based on the comparison with experimental data.

Van der Waals Interactions and Anharmonicity in the Lattice Vibrations, Dielectric Constants, Effective Charges, and Infrared Spectra of the Organic–Inorganic Halide Perovskite CH3NH3PbI3

The Journal of Physical Chemistry C

Scientific data, Jul 4, 2017

Electronic transport in materials is governed by a series of tensorial properties such as conduct... more Electronic transport in materials is governed by a series of tensorial properties such as conductivity, Seebeck coefficient, and effective mass. These quantities are paramount to the understanding of materials in many fields from thermoelectrics to electronics and photovoltaics. Transport properties can be calculated from a material's band structure using the Boltzmann transport theory framework. We present here the largest computational database of electronic transport properties based on a large set of 48,000 materials originating from the Materials Project database. Our results were obtained through the interpolation approach developed in the BoltzTraP software, assuming a constant relaxation time. We present the workflow to generate the data, the data validation procedure, and the database structure. Our aim is to target the large community of scientists developing materials selection strategies and performing studies involving transport properties.

J. Mater. Chem. C, 2017

We demonstrate through first principles computations how the metal–oxygen–metal angle directly dr... more We demonstrate through first principles computations how the metal–oxygen–metal angle directly drives the hole effective mass (thus the carrier mobility) in p-type s-orbital-based oxides.

Physical chemistry chemical physics : PCCP, Jan 17, 2017

Bournonite (CuPbSbS3) is an earth-abundant mineral with potential thermoelectric applications. Th... more Bournonite (CuPbSbS3) is an earth-abundant mineral with potential thermoelectric applications. This material has a complex crystal structure (space group Pmn21 #31) and has previously been measured to exhibit a very low thermal conductivity (κ < 1 W m(-1) K(-1) at T ≥ 300 K). In this study, we employ high-throughput density functional theory calculations to investigate how the properties of the bournonite crystal structure change with elemental substitutions. Specifically, we compute the stability and electronic properties of 320 structures generated via substitutions {Na-K-Cu-Ag}{Si-Ge-Sn-Pb}{N-P-As-Sb-Bi}{O-S-Se-Te} in the ABCD3 formula. We perform two types of transport calculations: the BoltzTraP model, which has been extensively tested, and a newer AMSET model that we have developed and which incorporates scattering effects. We discuss the differences in the model results, finding qualitative agreement except in the case of degenerate bands. Based on our calculations, we ide...