TY - JOUR
T1 - Local force method for the ab initio tight-binding model
T2 - Effect of spin-dependent hopping on exchange interactions
AU - Nomoto, Takuya
AU - Koretsune, Takashi
AU - Arita, Ryotaro
N1 - Funding Information:
We are grateful to Y. Kato, A. Terasawa, H. Shinaoka, and T. Miyake for many valuable discussions. This work was supported by a Grant-in-Aid for Scientific Research (No. 19K14654, No. 19H05825, No. 19H00650, No. 18K03442, and No. 16H06345) from Ministry of Education, Culture, Sports, Science and Technology, and CREST (JPMJCR18T3) from the Japan Science and Technology Agency.
Publisher Copyright:
© 2020 American Physical Society.
PY - 2020/7/1
Y1 - 2020/7/1
N2 - To estimate the Curie temperature of metallic magnets from first principles, we develop a local force method for the tight-binding model having spin-dependent hopping derived from spin-density-functional theory. While spin-dependent hopping is crucial for the self-consistent mapping to the effective spin model, the numerical cost to treat such nonlocal terms in the conventional Green's function scheme is formidably expensive. Here, we propose a formalism based on the kernel polynomial method (KPM), which makes the calculation dramatically efficient. We perform a benchmark calculation for bcc-Fe, fcc-Co, and fcc-Ni and find that the effect of the magnetic nonlocal terms is particularly prominent for bcc-Fe. We also present several local approximations to the magnetic nonlocal terms for which we can apply the Green's function method and reduce the numerical cost further by exploiting the intermediate representation of the Green's function. By comparing the results of the KPM and local methods, we discuss which local method works most successfully. Our approach provides an efficient way to estimate the Curie temperature of metallic magnets with a complex spin configuration.
AB - To estimate the Curie temperature of metallic magnets from first principles, we develop a local force method for the tight-binding model having spin-dependent hopping derived from spin-density-functional theory. While spin-dependent hopping is crucial for the self-consistent mapping to the effective spin model, the numerical cost to treat such nonlocal terms in the conventional Green's function scheme is formidably expensive. Here, we propose a formalism based on the kernel polynomial method (KPM), which makes the calculation dramatically efficient. We perform a benchmark calculation for bcc-Fe, fcc-Co, and fcc-Ni and find that the effect of the magnetic nonlocal terms is particularly prominent for bcc-Fe. We also present several local approximations to the magnetic nonlocal terms for which we can apply the Green's function method and reduce the numerical cost further by exploiting the intermediate representation of the Green's function. By comparing the results of the KPM and local methods, we discuss which local method works most successfully. Our approach provides an efficient way to estimate the Curie temperature of metallic magnets with a complex spin configuration.
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U2 - 10.1103/PhysRevB.102.014444
DO - 10.1103/PhysRevB.102.014444
M3 - Article
AN - SCOPUS:85090131351
VL - 102
JO - Physical Review B
JF - Physical Review B
SN - 2469-9950
IS - 1
M1 - 014444
ER -