The Monte Carlo method is one of the first and most widely used algorithms in modern computational physics.In condensed matter physics,the particularly popular flavor of this technique is the Metropolis Monte Carlo sc...The Monte Carlo method is one of the first and most widely used algorithms in modern computational physics.In condensed matter physics,the particularly popular flavor of this technique is the Metropolis Monte Carlo scheme.While being incredibly robust and easy to implement,the Metropolis sampling is not well-suited for situations where energy and force evaluations are computationally demanding.In search for a more efficient technique,we here explore the performance of Hybrid Monte Carlo sampling,an algorithm widely used in quantum electrodynamics,as a structure prediction scheme for systems with long-range interactions.Our results show that the Hybrid Monte Carlo algorithm stands out as an excellent computational scheme that can not only significantly outperform the Metropolis sampling but also complement molecular dynamics in materials science applications,while allowing ultra-large-scale simulations of systems containing millions of particles.展开更多
Electro-optic effects allow control of the ow of light using electric fields,and are of utmost importance for today’s information and communication technologies,such as TV displays and fiber optics.The search for lar...Electro-optic effects allow control of the ow of light using electric fields,and are of utmost importance for today’s information and communication technologies,such as TV displays and fiber optics.The search for large electro-optic constants in films is essential to the miniaturization and increased efficiency of electro-optic devices.In this work,we demonstrate that strain-engineering in PbTiO_(3) films allows to selectively choose which electro-optic constant to improve.Unclamped electro-optic constants larger than 100 pm V^(−1) are predicted,either by driving the softening of an optical phonon mode at a phase transition boundary under tensile strain,or by generating the equivalent of a negative pressure via compressive strain to obtain large piezoelectric constants.In particular,a r_(13) electro-optic coefficient twice as large as the one of the commonly used LiNbO_(3) electro-optic material is found here when growing PbTiO_(3) on the technologicallyimportant Si substrate.展开更多
After publishing this article,we realized that the calculation of the piezoelectric constants dij by Density Functional Perturbation Theory(DFPT),as explained in the methods described in the original version of the Su...After publishing this article,we realized that the calculation of the piezoelectric constants dij by Density Functional Perturbation Theory(DFPT),as explained in the methods described in the original version of the Supplementary Information,are incorrect in the case of a partially clamped situation.The correct methodology is to inverse the subspace matrix of elastic constants.展开更多
基金S.P and L.B.thank the DARPA Grant HR0011-15-2-0038(MATRIX program)K.K.acknowledges a SURF grant from the state of Arkansas,Y.N.and L.B.thank the DARPA Grant No.HR0011727183-D18AP00010(TEE Program)+1 种基金All authors are grateful for support provided by NVIDIA via the NVIDIA GPU Grant.Computations were made possible thanks to the use of the Arkansas High Performance Computing Center and the Arkansas Economic Development Commission.DARPA Grant HR0011-15-2-0038(MATRIX program)DARPA Grant No.HR0011727183-D18AP00010(TEE Program),SURF grant from the state of Arkansas,NVIDIA GPU Grant.
文摘The Monte Carlo method is one of the first and most widely used algorithms in modern computational physics.In condensed matter physics,the particularly popular flavor of this technique is the Metropolis Monte Carlo scheme.While being incredibly robust and easy to implement,the Metropolis sampling is not well-suited for situations where energy and force evaluations are computationally demanding.In search for a more efficient technique,we here explore the performance of Hybrid Monte Carlo sampling,an algorithm widely used in quantum electrodynamics,as a structure prediction scheme for systems with long-range interactions.Our results show that the Hybrid Monte Carlo algorithm stands out as an excellent computational scheme that can not only significantly outperform the Metropolis sampling but also complement molecular dynamics in materials science applications,while allowing ultra-large-scale simulations of systems containing millions of particles.
基金C.P.thanks the AHPCC for use of computing ressources.C.P.and L.B.thank the ARO grant W911NF-16-1-0227.S.P.and L.B.acknowledge DARPA grant HR0011-15-2-0038(MATRIX program).
文摘Electro-optic effects allow control of the ow of light using electric fields,and are of utmost importance for today’s information and communication technologies,such as TV displays and fiber optics.The search for large electro-optic constants in films is essential to the miniaturization and increased efficiency of electro-optic devices.In this work,we demonstrate that strain-engineering in PbTiO_(3) films allows to selectively choose which electro-optic constant to improve.Unclamped electro-optic constants larger than 100 pm V^(−1) are predicted,either by driving the softening of an optical phonon mode at a phase transition boundary under tensile strain,or by generating the equivalent of a negative pressure via compressive strain to obtain large piezoelectric constants.In particular,a r_(13) electro-optic coefficient twice as large as the one of the commonly used LiNbO_(3) electro-optic material is found here when growing PbTiO_(3) on the technologicallyimportant Si substrate.
文摘After publishing this article,we realized that the calculation of the piezoelectric constants dij by Density Functional Perturbation Theory(DFPT),as explained in the methods described in the original version of the Supplementary Information,are incorrect in the case of a partially clamped situation.The correct methodology is to inverse the subspace matrix of elastic constants.
