Operator Representation and Class Transitions in Elementary Cellular Automata

We exploit the mirror and complementary symmetries of elementary cellular automata (ECAs) to rewrite their rules in terms of logical operators. The operator representation based on these fundamental symmetries enables us to construct a periodic table of ECAs that maps all unique rules in clusters of similar asymptotic behavior. We also expand the elementary cellular automaton (ECA) dynamics by introducing a parameter that scales the pace with which operators iterate the system. While tuning this parameter continuously, further emergent behavior in ECAs is unveiled as several rules undergo multiple phase transitions between periodic, chaotic and complex (class 4) behavior. This extension provides an environment for studying class transitions and complex behavior in ECAs. Moreover, the emergence of class 4 structures can potentially enlarge the capacity of many ECA rules for universal computation

Structural and electronic properties of monolayer group III monochalcogenides (conferenceObject)

National Meeting of the American-Chemical-Society (ACS) -- MAR 31-APR 04, 2019 -- Orlando, FLWOS: 000478860504862…Amer Chem So

Temperature, strain and charge mediated multiple and dynamical phase changes of selenium and tellurium

Demirci, Salih/0000-0002-1272-9603; Jahangirov, Seymur/0000-0002-0548-4820WOS: 000516533300035PubMed: 31970352Semiconducting selenium and tellurium in their 3D bulk trigonal structures consist of parallel and weakly interacting helical chains of atoms and display a number of peculiarities. We predict that thermal excitations, 2D compressive strain and excess charge of positive and negative polarity mediate metal-insulator transitions by transforming these semiconductors into different metallic crystal structures. When heated to high temperature, or compressed, or charged positively, they change into a simple cubic structure with metallic bands, which is very rare among elemental crystals. When charged negatively, they transform first into body-centered tetragonal and subsequently into the body-centered orthorhombic structures with increasing negative charging. These two new structures stabilized by excess electrons also have overlapping metallic bands and quasi 2D and 1D substructures of lower dimensionality. Since the external charging of crystals can be achieved through their surfaces, the effects of charging on 2D structures of selenium and tellurium are also investigated. Similar structural transformations have been mediated also in 2D nanosheets and free-standing monolayers of these elements. These phase changes assisted by phonons are dynamical, reversible and tunable; the resulting metal-insulator transitions can occur within very short time intervals and may offer important device applications.Scientific and Technological Research Council of Turkey (TuBTAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [118F097]; National Center for High Performance Computing of Turkey (UHeM)Istanbul Technical University [5004132016]; TuBA, Turkish Academy of Sciences The Academy of Science of Turkey; The Academy of Science of Turkey - Outstanding Young Scientists Award Program (TuBA-GEBIP)This work was supported by the Scientific and Technological Research Council of Turkey (TuBTAK) under Project No 118F097. The computational resources are provided by TuBITAK ULAKBM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure) and the National Center for High Performance Computing of Turkey (UHeM) under Grant No. 5004132016. S. D. thanks UNAM, National Nanotechnology Center at Bilkent University for the hospitality. S. C. thanks TuBA, Turkish Academy of Sciences The Academy of Science of Turkey for the financial Support. S. J. acknowledges support from The Academy of Science of Turkey - Outstanding Young Scientists Award Program (TuBA-GEBIP)

Monolayer diboron dinitride: Direct band-gap semiconductor with high absorption in the visible range

Ershad Rad, Soheil/0000-0001-8947-9625WOS: 000518534400009We predict a two-dimensional monolayer polymorph of boron nitride in an orthorhombic structure (o-B2N2) using first-principles calculations. Structural optimization, phonon dispersion, and molecular dynamics calculations show that o-B2N2 is thermally and dynamically stable. o-B2N2 is a semiconductor with a direct band gap of 1.70 eV according to calculations based on hybrid functionals. The structure has high optical absorption in the visible range in the armchair direction while low absorption in the zigzag direction. This anisotropy is also present in electronic and mechanical properties. The in-plane stiffness of o-B2N2 is very close to that of hexagonal boron nitride. The diatomic building blocks of this structure hint at its possible synthesis from precursors having B-B and N-N bonds.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [118F097]; Turkish Academy of Sciences-Outstanding Young Scientists Award Program (TUBA-GEBIP)Turkish Academy of Sciences; National Center for High Performance Computing of Turkey (UHeM)Istanbul Technical University [5003622015]This work was supported by the Scientific and Technological Research Council of Turkey (TUBITAK) under Project No. 118F097. S.J. acknowledges support from the Turkish Academy of Sciences-Outstanding Young Scientists Award Program (TUBA-GEBIP). Part of the computational resources is provided by the National Center for High Performance Computing of Turkey (UHeM) under Grant No. 5003622015. S.D. thanks UNAM, National Nanotechnology Research Center at Bilkent University for the hospitality