Papers by Amir-Abbas Haghighirad
BaNi2As2 exhibits a variety of electronic phases, encompassing a charge density waves (CDW) which... more BaNi2As2 exhibits a variety of electronic phases, encompassing a charge density waves (CDW) which is supressed below a structural transition to a triclinic phase (TS=137 K), in which superconductivity appears (Tc=0.7 K). The interplay between all these phases remains unclear, and to gain further insights, we have recently investigated (proposal HC-4234) the response of the CDW in BaNi2As2 to hydrostatic pressure (HP) using single crystal x-ray diffraction (XRD). The purpose of the present proposal is to extend these measurements to P- doped BaNi2As2 to get insight into the origin of the CDW and their interplay with the other phases.
Iridium-containing oxide magnets are interesting because the different interactions controlling t... more Iridium-containing oxide magnets are interesting because the different interactions controlling their magnetic properties have similar energies associated with them. This leads to a competition between the interactions and a rich variety of ground states. Ba5AlIr2O11 shows the results of this competition in two particular ways - iridium ions have two different oxidation states (4+ and 5+) and the magnetic moment is much smaller than might otherwise be expected. We propose to investigate the magnetic ground state of this new material with muons because they are a particularly effective microscopic probe of iridium-containing magnets, and also look at the details of the magnetic phase transition to gain a greater understanding of the magnetic interactions in this material.
BaNi2As2 exhibits a variety of electronic phases, encompassing a charge density waves (CDW) which... more BaNi2As2 exhibits a variety of electronic phases, encompassing a charge density waves (CDW) which is supressed below a structural transition to a triclinic phase (TS=137 K), in which superconductivity appears (Tc=0.7 K). The interplay between all these phases remains unclear, and to gain further insights, we have recently investigated (proposal HC-4234) the response of the CDW in BaNi2As2 to hydrostatic pressure (HP) using single crystal x-ray diffraction (XRD). The purpose of the present proposal is to extend these measurements to P- doped BaNi2As2 to get insight into the origin of the CDW and their interplay with the other phases.
Iridium-containing oxide magnets are interesting because the different interactions controlling t... more Iridium-containing oxide magnets are interesting because the different interactions controlling their magnetic properties have similar energies associated with them. This leads to a competition between the interactions and a rich variety of ground states. Ba5AlIr2O11 shows the results of this competition in two particular ways - iridium ions have two different oxidation states (4+ and 5+) and the magnetic moment is much smaller than might otherwise be expected. We propose to investigate the magnetic ground state of this new material with muons because they are a particularly effective microscopic probe of iridium-containing magnets, and also look at the details of the magnetic phase transition to gain a greater understanding of the magnetic interactions in this material.
2019 IEEE 46th Photovoltaic Specialists Conference (PVSC), 2019
У статті наведено аналіз сучасного стану роботи з виховання основ культури споживання у дітей ста... more У статті наведено аналіз сучасного стану роботи з виховання основ культури споживання у дітей старшого дошкільного віку у практиці роботи ДНЗ. Подані матеріали аналізу річних планів роботи ДНЗ та календарних планів навчально-виховної роботи вихователів із дітьми старшого дошкільного віку. Виявлені особливості планування завдань, методи та прийоми, форми роботи з економічного виховання дітей старшого дошкільного віку взагалі та основ культури споживання зокрема. Ключові слова: основи культури споживання, економічне виховання, діти старшого дошкільного віку, форми, методи та прийоми. Ключевые слова: основы культуры потребления, экономическое воспитание, дети старшего дошкольного возраста, формы, методы и приемы. The paper presents an analysis of the current state of educating the foundations of consumption culture in preschool children in the practice of kindergartens. Material analysis of annual work plans and timetables for preschool educational work of caregivers with children under school age is given. The features of scheduling methods and techniques, forms of economic education of preschool children in general and foundations of consumption culture in particular are discussed.
Bulletin of the American Physical Society, 2020
2019 IEEE 46th Photovoltaic Specialists Conference (PVSC), 2019
У статті наведено аналіз сучасного стану роботи з виховання основ культури споживання у дітей ста... more У статті наведено аналіз сучасного стану роботи з виховання основ культури споживання у дітей старшого дошкільного віку у практиці роботи ДНЗ. Подані матеріали аналізу річних планів роботи ДНЗ та календарних планів навчально-виховної роботи вихователів із дітьми старшого дошкільного віку. Виявлені особливості планування завдань, методи та прийоми, форми роботи з економічного виховання дітей старшого дошкільного віку взагалі та основ культури споживання зокрема. Ключові слова: основи культури споживання, економічне виховання, діти старшого дошкільного віку, форми, методи та прийоми. Ключевые слова: основы культуры потребления, экономическое воспитание, дети старшего дошкольного возраста, формы, методы и приемы. The paper presents an analysis of the current state of educating the foundations of consumption culture in preschool children in the practice of kindergartens. Material analysis of annual work plans and timetables for preschool educational work of caregivers with children under school age is given. The features of scheduling methods and techniques, forms of economic education of preschool children in general and foundations of consumption culture in particular are discussed.
Bulletin of the American Physical Society, 2020
Physical Review B, 2020
By band engineering the iron chalcogenide Fe(Se,Te) via ab-initio calculations, we search for top... more By band engineering the iron chalcogenide Fe(Se,Te) via ab-initio calculations, we search for topological surface states and realizations of Majorana bound states. Proposed topological states are expected to occur for non-stoichiometric compositions on a surface Dirac cone where issues like disorder scattering and charge transfer between relevant electronic states have to be addressed. However, this surface Dirac cone is well above the Fermi-level. Our goal is to theoretically design a substituted crystal in which the surface Dirac cone is shifted towards the Fermi-level by modifying the bulk material without disturbing the surface. Going beyond conventional density functional theory (DFT), we apply the coherent potential approximation (BEB-CPA) in a mixed basis pseudopotential framework to scan the substitutional phase-space of co-substitutions on the Se-sites. We have identified iodine as a promising candidate for intrinsic doping. Our specific proposal is that FeSe0.325I0.175Te0.5 is a very likely candidate to exhibit a Dirac cone right at the Fermi energy without inducing strong disorder scattering.
Physical Review B, 2020
By band engineering the iron chalcogenide Fe(Se,Te) via ab-initio calculations, we search for top... more By band engineering the iron chalcogenide Fe(Se,Te) via ab-initio calculations, we search for topological surface states and realizations of Majorana bound states. Proposed topological states are expected to occur for non-stoichiometric compositions on a surface Dirac cone where issues like disorder scattering and charge transfer between relevant electronic states have to be addressed. However, this surface Dirac cone is well above the Fermi-level. Our goal is to theoretically design a substituted crystal in which the surface Dirac cone is shifted towards the Fermi-level by modifying the bulk material without disturbing the surface. Going beyond conventional density functional theory (DFT), we apply the coherent potential approximation (BEB-CPA) in a mixed basis pseudopotential framework to scan the substitutional phase-space of co-substitutions on the Se-sites. We have identified iodine as a promising candidate for intrinsic doping. Our specific proposal is that FeSe0.325I0.175Te0.5 is a very likely candidate to exhibit a Dirac cone right at the Fermi energy without inducing strong disorder scattering.
Nano Letters, 2020
Magnetic skyrmions are two-dimensional magnetization swirls that stack in the form of tubes in th... more Magnetic skyrmions are two-dimensional magnetization swirls that stack in the form of tubes in the third dimension and which are proposed as prospective information carriers for nonvolatile memory devices due to their unique topological properties. From resonant elastic X-ray scattering measurements on Cu 2 OSeO 3 with an in-plane magnetic field, we find that a state of perpendicularly ordered skyrmions forms, in stark contrast to the well-studied bulk state. The surface state is stable over a wide temperature range, unlike the bulk state in out-of-plane fields which is confined to a narrow region of the temperaturefield phase diagram. In contrast to ordinary skyrmions found in the bulk, the surface state skyrmions result from the presence of magnetic interactions unique to the surface which stabilize them against external perturbations. The surface guiding makes the robust state particular interesting for racetracklike devices, ultimately allowing for much higher storage densities due to the smaller lateral footprint of the perpendicular skyrmions.
Nano Letters, 2020
Magnetic skyrmions are two-dimensional magnetization swirls that stack in the form of tubes in th... more Magnetic skyrmions are two-dimensional magnetization swirls that stack in the form of tubes in the third dimension and which are proposed as prospective information carriers for nonvolatile memory devices due to their unique topological properties. From resonant elastic X-ray scattering measurements on Cu 2 OSeO 3 with an in-plane magnetic field, we find that a state of perpendicularly ordered skyrmions forms, in stark contrast to the well-studied bulk state. The surface state is stable over a wide temperature range, unlike the bulk state in out-of-plane fields which is confined to a narrow region of the temperaturefield phase diagram. In contrast to ordinary skyrmions found in the bulk, the surface state skyrmions result from the presence of magnetic interactions unique to the surface which stabilize them against external perturbations. The surface guiding makes the robust state particular interesting for racetracklike devices, ultimately allowing for much higher storage densities due to the smaller lateral footprint of the perpendicular skyrmions.
Journal of Materials Chemistry A, 2019
The power conversion efficiency (PCE) of lead-halide perovskite solar cells (PSCs) is reported to... more The power conversion efficiency (PCE) of lead-halide perovskite solar cells (PSCs) is reported to increase over a period of days after their fabrication while they are stored in dark. Thus...
Journal of Materials Chemistry A, 2019
The power conversion efficiency (PCE) of lead-halide perovskite solar cells (PSCs) is reported to... more The power conversion efficiency (PCE) of lead-halide perovskite solar cells (PSCs) is reported to increase over a period of days after their fabrication while they are stored in dark. Thus...
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Papers by Amir-Abbas Haghighirad