TY - JOUR

T1 - Strong-coupling formula for momentum-dependent susceptibilities in dynamical mean-field theory

AU - Otsuki, Junya

AU - Yoshimi, Kazuyoshi

AU - Shinaoka, Hiroshi

AU - Nomura, Yusuke

N1 - Funding Information:
We acknowledge useful discussions with S. Ishihara, M. Naka, J. Kuneš, H. Ikeda, Y. Ōno, T. Yamada, and Y. Iizuka. The numerical calculations were performed using the following open source libraries and softwares: TRIQS [41] , DFTTools [42] , pomerol [43] , pomerol2triqs , and pomerol2triqs1.4 . We were supported by JSPS KAKENHI Grant No. 18H01158. J.O. was supported by JSPS KAKENHI Grant No. 18H04301 (J-Physics). K.Y. was supported by Building of Consortia for the Development of Human Resources in Science and Technology, MEXT, Japan. H.S. was supported by JSPS KAKENHI Grant No. 16K17735. Y.N. was supported by JSPS KAKENHI Grants No. 16H06345 and No. 17K14336.
Publisher Copyright:
© 2019 American Physical Society.

PY - 2019/4/23

Y1 - 2019/4/23

N2 - Computing momentum-dependent susceptibilities in the dynamical mean-field theory (DMFT) requires solving the Bethe-Salpeter equation, which demands large computational cost. Exploiting the strong-coupling feature of local fluctuations, we derive a simplified formula that can be solved at a considerably lower cost. The validity and the physical meaning of the formula are confirmed by deriving the effective intersite interactions in the strong-coupling limit, such as the kinetic exchange and RKKY interactions. Furthermore, numerical calculations for single-orbital and multiorbital models demonstrate surprisingly wider applicability including a weak-coupling region. Based on this formula, we propose three levels of practical approximations that can be chosen depending on complexity of problems. Simpler evaluations of spin and orbital susceptibilities in multiorbital systems thus become possible within DMFT.

AB - Computing momentum-dependent susceptibilities in the dynamical mean-field theory (DMFT) requires solving the Bethe-Salpeter equation, which demands large computational cost. Exploiting the strong-coupling feature of local fluctuations, we derive a simplified formula that can be solved at a considerably lower cost. The validity and the physical meaning of the formula are confirmed by deriving the effective intersite interactions in the strong-coupling limit, such as the kinetic exchange and RKKY interactions. Furthermore, numerical calculations for single-orbital and multiorbital models demonstrate surprisingly wider applicability including a weak-coupling region. Based on this formula, we propose three levels of practical approximations that can be chosen depending on complexity of problems. Simpler evaluations of spin and orbital susceptibilities in multiorbital systems thus become possible within DMFT.

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U2 - 10.1103/PhysRevB.99.165134

DO - 10.1103/PhysRevB.99.165134

M3 - Article

AN - SCOPUS:85065136483

SN - 2469-9950

VL - 99

JO - Physical Review B-Condensed Matter

JF - Physical Review B-Condensed Matter

IS - 16

M1 - 165134

ER -