Questaal Home
Navigation

News Categories


papers lmto lmpg dmft qsgw article qsgw bse ladder phonons workshop lmf nonequilibrium green's functions tb-lmto-cpa layer green's function qsgw, dmft, bse superconductivity dft, qsgw, dmft bse magnetism yig scattering

News By Category


PAPERS

First-principles supercurrent calculations in realistic magnetic Josephson junctions

Detailed electronic structure calculations for a proper description of the transport properties of magnetic Josephson junctions

Magnetism of Yttrium Iron Garnet

QSGW provides a parameter free description of magnetism in the YIG, the model material for spintronics and magnonics research

Origins of Superconductivity in LaFe<sub>2</sub>As<sub>2</sub> and CaFe<sub>2</sub>As<sub>2</sub>

How incoherence from Hundness controls superconductivity in LaFe2As2 and CaFe2As2

Questaal Methods Paper

A paper describing Questaal's functionality, including its basis set, its various implementations of density-functional theory and its two tracks of many-body theory.

Ab initio Description of Superconductivity in Sr<sub>2</sub>RuO<sub>4</sub>

How spin and charge parity combine to increase the superconducting critical temperature in Sr2RuO4 under strain

Density-functional Description of Spin Orbit Torque

Interfacial contribution to spin-orbit torque and magnetoresistance in ferromagnet/heavy-metal bilayers

Electrical transport of tetragonal CuMnAs

TB-LMTO-CPA was used to model electrical transport in tetragonal CuMnAs at finite temperature.

Hyperbolic Optical Dispersion in CuS

Anisotropic Plasmonic CuS Nanocrystals as a Natural Electronic Material with Hyperbolic Optical Dispersion

Energy band structure and optical properties of boron arsenide

State-of-the-art calculation of the electronic and optical properties of the newly emerging thermal transport semiconductor boron arsenide

Spin-orbit Torques in CoPt Multilayers

We have demonstrated the feasibility of calculating the spin-orbit torques in layered systems within density-functional theory, augmented by an Anderson model to treat disorder. Terms beyond the usual damping-like and field-like torques were found. While the torques that contribute to damping are almost entirely due to spin-orbit coupling on the Pt atoms, the field-like torque does not require it.

Metal-insulator transition in copper oxides induced by apex displacements

The Quasiparticle Self-Consistent GW approximation is combined with Dynamical Mean Field theory (DMFT). It is shown that by varying the positions of apical oxygen atoms, a metal-insulator transition can be induced in La2CuO4. This work also shows that optical conductivity can be well predicted by the theory and shows how spin and charge susceptibilities and the superconducting pairing order parameter, vary with the apical O displacement. QSGW+DMFT provides a new approach to handle strong correlations with predictive capability greatly superior to conventional methods such as DFT+DMFT.

Quasiparticle Self-Consistent GW

Metal-organic perovskite solar cells, CH3NH3PbI3 (MAPI) in particular, have attracted much attention recently because of their high power conversion efficiency and potential low cost.

QSGW + Spin-Dynamical Mean Field Theory Applied to Ni

Density-Functional theory, while being immensely popular thanks to its simplicity, nevertheless is limited in its reliability. The QuasiParticle Self-Consistent GW approximation, while more demanding than DFT, is vastly more reliable than DFT, or GW theory based on DFT, for calculation of optical properties in weakly correlated systems.

Principal Layer Green’s Functions

Many spintronic devices to emerge in recent years consist of spin transport through alternating, nanosized metallic layers

Green’s Functions LMTO

January 17, 2017 | PAPERS · LMTO

Green’s Functions LMTO

A new concept for very fast electronic devices has emerged in recent years. Called JMRAM, it relies on the rotation of the phase of a Cooper pair wave function when it passes through a thin magnetic layer.

LMTO

Green’s Functions LMTO

January 17, 2017 | PAPERS · LMTO

Green’s Functions LMTO

A new concept for very fast electronic devices has emerged in recent years. Called JMRAM, it relies on the rotation of the phase of a Cooper pair wave function when it passes through a thin magnetic layer.

LMPG

Principal Layer Green’s Functions

Many spintronic devices to emerge in recent years consist of spin transport through alternating, nanosized metallic layers

DMFT

Origins of Superconductivity in LaFe<sub>2</sub>As<sub>2</sub> and CaFe<sub>2</sub>As<sub>2</sub>

How incoherence from Hundness controls superconductivity in LaFe2As2 and CaFe2As2

Metal-insulator transition in copper oxides induced by apex displacements

The Quasiparticle Self-Consistent GW approximation is combined with Dynamical Mean Field theory (DMFT). It is shown that by varying the positions of apical oxygen atoms, a metal-insulator transition can be induced in La2CuO4. This work also shows that optical conductivity can be well predicted by the theory and shows how spin and charge susceptibilities and the superconducting pairing order parameter, vary with the apical O displacement. QSGW+DMFT provides a new approach to handle strong correlations with predictive capability greatly superior to conventional methods such as DFT+DMFT.

QSGW + Spin-Dynamical Mean Field Theory Applied to Ni

Density-Functional theory, while being immensely popular thanks to its simplicity, nevertheless is limited in its reliability. The QuasiParticle Self-Consistent GW approximation, while more demanding than DFT, is vastly more reliable than DFT, or GW theory based on DFT, for calculation of optical properties in weakly correlated systems.

QSGW

Magnetism of Yttrium Iron Garnet

QSGW provides a parameter free description of magnetism in the YIG, the model material for spintronics and magnonics research

Origins of Superconductivity in LaFe<sub>2</sub>As<sub>2</sub> and CaFe<sub>2</sub>As<sub>2</sub>

How incoherence from Hundness controls superconductivity in LaFe2As2 and CaFe2As2

Electrical transport of tetragonal CuMnAs

TB-LMTO-CPA was used to model electrical transport in tetragonal CuMnAs at finite temperature.

Hyperbolic Optical Dispersion in CuS

Anisotropic Plasmonic CuS Nanocrystals as a Natural Electronic Material with Hyperbolic Optical Dispersion

Energy band structure and optical properties of boron arsenide

State-of-the-art calculation of the electronic and optical properties of the newly emerging thermal transport semiconductor boron arsenide

Quasiparticle Self-Consistent GW

Metal-organic perovskite solar cells, CH3NH3PbI3 (MAPI) in particular, have attracted much attention recently because of their high power conversion efficiency and potential low cost.

ARTICLE

Frolich contribution to energy band shifts in SrTiO<sub>3</sub>

The Lambrecht group at Case Western University estimated how phonons modify the band structure in SrTiO3. Isolating the Frolich part of the electron-phonon interaction (which is the dominant contribution for highly polar compounds), they estimated the reduction in the screened coulomb interaction W, and its effect on the QSGW band structure.

Ladder Diagrams in QSGW

December 5, 2017 | ARTICLE · QSGW · BSE · LADDER

Ladder Diagrams in QSGW

Recently, Brian Cunningham and Myrta Gruening incorporated ladder diagrams as an extension to the RPA polarizability. Ladder diagrams significantly improve agreement with experimental dielectric response functions. The QSGW framework makes it possible to address systems whose electronic structure is poorly described within the standard perturbative GW approaches with as a starting point density-functional theory calculations. The Figure shows the real and imaginary parts of the dielectric function for Ge.

QSGW

3rd Daresbury Questaal school

We are pleased to announce the 3rd Daresbury Questaal school. It will take place 13-17 May 2019, at Daresbury Laboratory, UK. This is an opportunity for researchers to learn about advanced electronic structure and gain hands-on experience with Questaal's DFT/QSGW/BSE/DMFT functionality. The event is free to attend and local accommodation will be provided.

Many body response functions in the Questaal code

A hands-on course highlighting Questaal's GW/DMFT/BSE capability. This is an opportunity for researchers to learn about advanced electronic structure and how to use the Questaal Suite.

Frolich contribution to energy band shifts in SrTiO<sub>3</sub>

The Lambrecht group at Case Western University estimated how phonons modify the band structure in SrTiO3. Isolating the Frolich part of the electron-phonon interaction (which is the dominant contribution for highly polar compounds), they estimated the reduction in the screened coulomb interaction W, and its effect on the QSGW band structure.

Ladder Diagrams in QSGW

December 5, 2017 | ARTICLE · QSGW · BSE · LADDER

Ladder Diagrams in QSGW

Recently, Brian Cunningham and Myrta Gruening incorporated ladder diagrams as an extension to the RPA polarizability. Ladder diagrams significantly improve agreement with experimental dielectric response functions. The QSGW framework makes it possible to address systems whose electronic structure is poorly described within the standard perturbative GW approaches with as a starting point density-functional theory calculations. The Figure shows the real and imaginary parts of the dielectric function for Ge.

BSE

Ladder Diagrams in QSGW

December 5, 2017 | ARTICLE · QSGW · BSE · LADDER

Ladder Diagrams in QSGW

Recently, Brian Cunningham and Myrta Gruening incorporated ladder diagrams as an extension to the RPA polarizability. Ladder diagrams significantly improve agreement with experimental dielectric response functions. The QSGW framework makes it possible to address systems whose electronic structure is poorly described within the standard perturbative GW approaches with as a starting point density-functional theory calculations. The Figure shows the real and imaginary parts of the dielectric function for Ge.

LADDER

Ladder Diagrams in QSGW

December 5, 2017 | ARTICLE · QSGW · BSE · LADDER

Ladder Diagrams in QSGW

Recently, Brian Cunningham and Myrta Gruening incorporated ladder diagrams as an extension to the RPA polarizability. Ladder diagrams significantly improve agreement with experimental dielectric response functions. The QSGW framework makes it possible to address systems whose electronic structure is poorly described within the standard perturbative GW approaches with as a starting point density-functional theory calculations. The Figure shows the real and imaginary parts of the dielectric function for Ge.

PHONONS

Frolich contribution to energy band shifts in SrTiO<sub>3</sub>

The Lambrecht group at Case Western University estimated how phonons modify the band structure in SrTiO3. Isolating the Frolich part of the electron-phonon interaction (which is the dominant contribution for highly polar compounds), they estimated the reduction in the screened coulomb interaction W, and its effect on the QSGW band structure.

WORKSHOP

3rd Daresbury Questaal school

We are pleased to announce the 3rd Daresbury Questaal school. It will take place 13-17 May 2019, at Daresbury Laboratory, UK. This is an opportunity for researchers to learn about advanced electronic structure and gain hands-on experience with Questaal's DFT/QSGW/BSE/DMFT functionality. The event is free to attend and local accommodation will be provided.

Many body response functions in the Questaal code

A hands-on course highlighting Questaal's GW/DMFT/BSE capability. This is an opportunity for researchers to learn about advanced electronic structure and how to use the Questaal Suite.

LMF

3rd Daresbury Questaal school

We are pleased to announce the 3rd Daresbury Questaal school. It will take place 13-17 May 2019, at Daresbury Laboratory, UK. This is an opportunity for researchers to learn about advanced electronic structure and gain hands-on experience with Questaal's DFT/QSGW/BSE/DMFT functionality. The event is free to attend and local accommodation will be provided.

Many body response functions in the Questaal code

A hands-on course highlighting Questaal's GW/DMFT/BSE capability. This is an opportunity for researchers to learn about advanced electronic structure and how to use the Questaal Suite.

NONEQUILIBRIUM GREEN'S FUNCTIONS

Spin-orbit Torques in CoPt Multilayers

We have demonstrated the feasibility of calculating the spin-orbit torques in layered systems within density-functional theory, augmented by an Anderson model to treat disorder. Terms beyond the usual damping-like and field-like torques were found. While the torques that contribute to damping are almost entirely due to spin-orbit coupling on the Pt atoms, the field-like torque does not require it.

TB-LMTO-CPA

Electrical transport of tetragonal CuMnAs

TB-LMTO-CPA was used to model electrical transport in tetragonal CuMnAs at finite temperature.

LAYER GREEN'S FUNCTION

Density-functional Description of Spin Orbit Torque

Interfacial contribution to spin-orbit torque and magnetoresistance in ferromagnet/heavy-metal bilayers

QSGW, DMFT, BSE

Ab initio Description of Superconductivity in Sr<sub>2</sub>RuO<sub>4</sub>

How spin and charge parity combine to increase the superconducting critical temperature in Sr2RuO4 under strain

SUPERCONDUCTIVITY

First-principles supercurrent calculations in realistic magnetic Josephson junctions

Detailed electronic structure calculations for a proper description of the transport properties of magnetic Josephson junctions

Origins of Superconductivity in LaFe<sub>2</sub>As<sub>2</sub> and CaFe<sub>2</sub>As<sub>2</sub>

How incoherence from Hundness controls superconductivity in LaFe2As2 and CaFe2As2

Questaal Methods Paper

A paper describing Questaal's functionality, including its basis set, its various implementations of density-functional theory and its two tracks of many-body theory.

Ab initio Description of Superconductivity in Sr<sub>2</sub>RuO<sub>4</sub>

How spin and charge parity combine to increase the superconducting critical temperature in Sr2RuO4 under strain

DFT, QSGW, DMFT

Questaal Methods Paper

A paper describing Questaal's functionality, including its basis set, its various implementations of density-functional theory and its two tracks of many-body theory.

BSE

Origins of Superconductivity in LaFe<sub>2</sub>As<sub>2</sub> and CaFe<sub>2</sub>As<sub>2</sub>

How incoherence from Hundness controls superconductivity in LaFe2As2 and CaFe2As2

MAGNETISM

First-principles supercurrent calculations in realistic magnetic Josephson junctions

Detailed electronic structure calculations for a proper description of the transport properties of magnetic Josephson junctions

Magnetism of Yttrium Iron Garnet

QSGW provides a parameter free description of magnetism in the YIG, the model material for spintronics and magnonics research

YIG

Magnetism of Yttrium Iron Garnet

QSGW provides a parameter free description of magnetism in the YIG, the model material for spintronics and magnonics research

SCATTERING

First-principles supercurrent calculations in realistic magnetic Josephson junctions

Detailed electronic structure calculations for a proper description of the transport properties of magnetic Josephson junctions