First-principles KKR-CPA calculation of interactions between concentration fluctuations

Long, Nguyễn Hoàng; Akai, H.

doi:10.1088/0953-8984/19/36/365232

Cited by 9 publications

(3 citation statements)

References 11 publications

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“…The magnetic and transport measurements were performed using a superconducting quantum interference device magnetometer (MPMS, Quantum Design) and Physics property measurement system (PPMS, Quantum Design), respectively. The electronic band structure is calculated by employing the coherent potential approximation (CPA) 10 for nonstoichiometric situation. Actually,…”

mentioning

confidence: 99%

Magneto-transport properties of oriented Mn2CoAl films sputtered on thermally oxidized Si substrates

Xu¹,

Du²,

Zhang³

et al. 2014

Applied Physics Letters

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Spin gapless semiconductors are interesting novel class of materials by embracing both magnetism and semiconducting. Its potential application in future spintronics requires realization in thin film form. In this letter, we report a successful growth of spin gapless Mn 2 CoAl films on thermally oxidized Si substrates by magnetron sputtering deposition. The films deposited at 673K are well oriented to (001) direction and display a uniform-crystalline surface. Magnetotransport measurements on the oriented films reveal a semiconducting-like resistivity, small anomalous Hall conductivity and linear magnetoresistance (MR) representative of the transport signatures of spin gapless semiconductors. The magnetic properties of the films have also been investigated and compared to that of bulk Mn 2 CoAl, with small discrepancy induced by the composition deviation.------------------------------a) Author to whom correspondence should be addressed. . In this letter, we report the growth of oriented Mn 2 CoAl films on thermally oxidized Si substrates using magnetron sputtering.Magnetotransport measurements on the oriented films revealed a semiconducting-like resistivity, small Hall conductivity and linear magnetoresistance indicative of the transport features of SGS.We have deposited a series of Mn 2 CoAl films on thermally oxidized Si substrates using magnetron sputtering system with the base pressure of below 5×10 -5 Pa. The optimized sample we chose for present study is deposited under an Ar pressure of 0.2Pa while the substrate was kept at 673K with dc power of 30W. The typical thickness of the film determined by the stylus profile is about 200-nm-thick under a deposition rate of ~4 Å/s. The structure was determined by X-ray diffraction (XRD) using the Cu-Kα radiation. The composition and morphology of the film were examined by scanning electron microscope (SEM) equipped with an energy-dispersive X-ray spectroscopy (EDX). The magnetic and transport measurements were performed using a superconducting quantum interference device magnetometer (MPMS, Quantum Design) and Physics property measurement system (PPMS, Quantum Design), respectively. The electronic band structure is calculated by employing the coherent potential approximation (CPA) The sign change of ( ) xx T  slope is commonly observed in semimetals or narrow-gap semiconductors where atomic disorder, defects or nonstoichiometry gives rise to impurity levels governing low temperature conduction. 11,12 In our case, the general shape of ( ) xx T  is characteristics of semimetals or doped semiconductors which can be described by an thermal activation model with a small energy gap. 13As shown in the inset of Fig. 2(a), the conductivity is well approximated by a simple model:, where 0  indicates possible nonstoichiometry generated conduction at low temperatures. The best parameter fit yields an energy gap of 90meVThe magnetoresistance (MR) in Fig. 2 , just equivalent to the slope, is actually a temperature independent value. We plot the Hall conductivity as a funct...

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mentioning

confidence: 99%

Magneto-transport properties of oriented Mn2CoAl films sputtered on thermally oxidized Si substrates

Xu¹,

Du²,

Zhang³

et al. 2014

Applied Physics Letters

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“…21) and 22). For the calculation of EPIs we employed the subroutine developed by Long et al 25) implemented to Akaikkr package. 23,26) Once the EPI's are determined we can generate atomic configurations in HEAs at finite temperature by performing MCS.…”

Section: Monte-carlo Simulation Of Atomic Configuration Inmentioning

confidence: 99%

Computational Materials Design of High-Entropy Alloys Based on Full Potential Korringa-Kohn-Rostoker Coherent Potential Approximation and Machine Learning Techniques

Sato,

Hayashi,

Ogushi

et al. 2023

Mater. Trans.

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Computational materials design (CMD) based on the first-principles electronic structure calculations is demonstrated for two topics related to the design of high-entropy alloys (HEAs). The first one is a construction of prediction model of elastic constants. By applying machine learning technique with the use of the linearly independent descriptor generation method to the database of elastic constants of 2555 BCC HEAs generated by the full potential Korringa-Kohn-Rostoker coherent potential approximation (FPKKR-CPA) method. The obtained model is used to predict new HEAs with high Young's modulus. The second topic is a simulation of atomic arrangement in HEAs at finite temperature. In this simulation, HEAs are described by using the Potts-like model and the interaction parameters are determined based on the generalized perturbation method combined with the KKR-CPA method. Monte Carlo simulations for the models of CrMnFeCoNi and CrMnFeCoCu predict atomic arrangements which are consistent to the experimental observations.

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“…Обчислення атомних i термодинамiчних властивостей напiвпровiдникiв з дефектами проводяться за допомогою атомних апрiорних псевдопотенцiалiв [3,5], однак застосування цього методу до систем з домiшками d-та f -елементiв на сьогоднi рiдкiснi. Тому ми виконали розрахунок електронної структури твердих розчинiв з домiшкою d-елемента за допомогою програми AkaiKKR [6], яка дає змогу проводити самоузгодженi розрахунки не тiльки сполук з перехiдними елементами, а й невпорядкованих систем [7]. Програма ґрунтується на розрахунку функцiї Грiна у кристалi [6]:…”

Section: розрахунокunclassified

Електронна структура твердих розчинів GaInN з домішками хрому і водню

Сиротюк¹,

Shved²

2021

Ukr. J. Phys.

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Електронні та магнітні властивості твердих розчинів GaInN з домішками хрому і водню було розраховано за методом функції Гріна. Отримані парціальні та повні спін-поляризовані щільності електронних станів вказують на докорінну перебудову електронної структури кристала, спричинену атомами заміщення Cr та міжвузловими домішковими атомами водню. Зміни пов'язані з появою у забороненій зоні вузьких гібридизованих зон s-, p- і d-симетрії, відсутніх у твердих розчинах GaInN.

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First-principles KKR-CPA calculation of interactions between concentration fluctuations

Cited by 9 publications

References 11 publications

Magneto-transport properties of oriented Mn2CoAl films sputtered on thermally oxidized Si substrates

Magneto-transport properties of oriented Mn2CoAl films sputtered on thermally oxidized Si substrates

Computational Materials Design of High-Entropy Alloys Based on Full Potential Korringa-Kohn-Rostoker Coherent Potential Approximation and Machine Learning Techniques

Електронна структура твердих розчинів GaInN з домішками хрому і водню

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