@article{wang_kincaid_zhou_annaberdiyev_bennett_krogel_mitas_2022, title={A new generation of effective core potentials from correlated and spin-orbit calculations: Selected heavy elements}, volume={157}, ISSN={["1089-7690"]}, DOI={10.1063/5.0087300}, abstractNote={We introduce new correlation consistent effective core potentials (ccECPs) for the elements I, Te, Bi, Ag, Au, Pd, Ir, Mo, and W with 4d, 5d, 6s, and 6p valence spaces. These ccECPs are given as a sum of spin-orbit averaged relativistic effective potential (AREP) and effective spin-orbit (SO) terms. The construction involves several steps with increasing refinements from more simple to fully correlated methods. The optimizations are carried out with objective functions that include weighted many-body atomic spectra, norm-conservation criteria, and SO splittings. Transferability tests involve molecular binding curves of corresponding hydride and oxide dimers. The constructed ccECPs are systematically better and in a few cases on par with previous effective core potential (ECP) tables on all tested criteria and provide a significant increase in accuracy for valence-only calculations with these elements. Our study confirms the importance of the AREP part in determining the overall quality of the ECP even in the presence of sizable spin-orbit effects. The subsequent quantum Monte Carlo calculations point out the importance of accurate trial wave functions that, in some cases (mid-series transition elements), require treatment well beyond a single-reference.}, number={5}, journal={JOURNAL OF CHEMICAL PHYSICS}, author={Wang, Guangming and Kincaid, Benjamin and Zhou, Haihan and Annaberdiyev, Abdulgani and Bennett, M. Chandler and Krogel, Jaron T. and Mitas, Lubos}, year={2022}, month={Aug} }
@article{zhou_scemama_wang_annaberdiyev_kincaid_caffarel_mitas_2022, title={A quantum Monte Carlo study of systems with effective core potentials and node nonlinearities}, volume={554}, ISSN={["1873-4421"]}, DOI={10.1016/j.chemphys.2021.111402}, abstractNote={We study beryllium dihydride (BeH$_2$) and acetylene (C$_2$H$_2$) molecules using real-space diffusion Monte Carlo (DMC) method. The molecules serve as perhaps the simplest prototypes that illustrate the difficulties with biases in the fixed-node DMC calculations that might appear with the use of effective core potentials (ECPs) or other nonlocal operators. This is especially relevant for the recently introduced correlation consistent ECPs (ccECPs) for $2s2p$ elements. Corresponding ccECPs exhibit deeper potential functions due to higher fidelity to all-electron counterparts, which could lead to larger local energy fluctuations. We point out that the difficulties stem from issues that are straightforward to address by upgrades of basis sets, use of T-moves for nonlocal terms, inclusion of a few configurations into the trial function and similar. The resulting accuracy corresponds to the ccECP target (chemical accuracy) and it is in consistent agreement with independent correlated calculations. Further possibilities for upgrading the reliability of the DMC algorithm and considerations for better adapted and more robust Jastrow factors are discussed as well.}, journal={CHEMICAL PHYSICS}, author={Zhou, Haihan and Scemama, Anthony and Wang, Guangming and Annaberdiyev, Abdulgani and Kincaid, Benjamin and Caffarel, Michel and Mitas, Lubos}, year={2022}, month={Feb} }
@article{kincaid_wang_zhou_mitas_2022, title={Correlation consistent effective core potentials for late 3d transition metals adapted for plane wave calculations}, volume={157}, ISSN={["1089-7690"]}, DOI={10.1063/5.0109098}, abstractNote={We construct a new modification of correlation consistent effective core potentials (ccECPs) for late 3 d elements Cr–Zn with Ne-core that are adapted for efficiency and low energy cut-offs in plane wave calculations. The decrease in accuracy is rather minor, so that the constructions are in the same overall accuracy class as the original ccECPs. The resulting new constructions work with energy cut-offs at or below ≈400 Ry and, thus, make calculations of large systems with transition metals feasible for plane wave codes. We also provide the basic benchmarks for atomic spectra and molecular tests of this modified option that we denote as ccECP-soft.}, number={17}, journal={JOURNAL OF CHEMICAL PHYSICS}, author={Kincaid, Benjamin and Wang, Guangming and Zhou, Haihan and Mitas, Lubos}, year={2022}, month={Nov} }
@misc{polash_yalameha_zhou_ahadi_nourbakhsh_vashaee_2021, title={Topological quantum matter to topological phase conversion: Fundamentals, materials, physical systems for phase conversions, and device applications}, volume={145}, ISSN={["1879-212X"]}, url={https://doi.org/10.1016/j.mser.2021.100620}, DOI={10.1016/j.mser.2021.100620}, abstractNote={The spin-orbit coupling field, an atomic magnetic field inside a Kramers’ system, or discrete symmetries can create a topological torus in the Brillouin Zone and provide protected edge or surface states, which can contain relativistic fermions, namely, Dirac and Weyl Fermions. The topology-protected helical edge or surface states and the bulk electronic energy band define different quantum or topological phases of matters, offering an excellent prospect for some unique device applications. Device applications of the quantum materials rely primarily on understanding the topological properties, their mutual conversion processes under different external stimuli, and the physical system for achieving the phase conversion. There have been tremendous efforts in finding new topological materials with exotic topological phases. However, the application of the topological properties in devices is still limited due to the slow progress in developing the physical structures for controlling the topological phase conversions. Such control systems often require extreme tuning conditions or the fabrication of complex multi-layered topological structures. This review article highlights the details of the topological phases, their conversion processes, along with their potential physical systems, and the prospective application fields. A general overview of the critical factors for topological phases and the materials properties are further discussed to provide the necessary background for the following sections.}, journal={MATERIALS SCIENCE & ENGINEERING R-REPORTS}, publisher={Elsevier BV}, author={Polash, Md Mobarak Hossain and Yalameha, Shahram and Zhou, Haihan and Ahadi, Kaveh and Nourbakhsh, Zahra and Vashaee, Daryoosh}, year={2021}, month={Jul} }
@article{zhou_li_zhang_long_2019, title={Quantum Random-Number Generator Based on Tunneling Effects in a Si Diode}, volume={11}, ISSN={["2331-7019"]}, DOI={10.1103/PhysRevApplied.11.034060}, abstractNote={Previously, we built up a set of photon-free quantum random number generator(QRNG) with InGaAs single photon avalanche diodes. We exploited the stochastic property of quantum tunneling effect. Here, we utilized tunneling signals in Si diodes to implement quantum random number generator. In our experiment, instead of applying periodic pulses between the diode as we did in the InGaAs QRNG, we applied fixed voltage and detect time intervals between adjacent tunneling signals, as random source. This Si QRNG has a high performance in the randomness of its raw data and almost post-processing-free. Final data rate in our experiment is 6.98MB/s and could reach 23MB/s if the temperature-control system is ameliorated.}, number={3}, journal={PHYSICAL REVIEW APPLIED}, author={Zhou, Haihan and Li, Junlin and Zhang, Weixing and Long, Gui-Lu}, year={2019}, month={Mar} }