Breakdown of the Migdal-Eliashberg theory: A determinant quantum Monte Carlo study

被引：87

作者：

Esterlis, I. ^{[1
]}

Nosarzewski, B. ^{[1
,2
,3
]}

Huang, E. W. ^{[1
,2
,3
]}

Moritz, B. ^{[2
,3
]}

Devereaux, T. P. ^{[2
,3
,4
]}

Scalapino, D. J. ^{[5
]}

Kivelson, S. A. ^{[1
,4
]}

机构：

[1] Stanford Univ, Dept Phys, Stanford, CA 94305 USA

[2] SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, Menlo Pk, CA 94025 USA

[3] Stanford Univ, Menlo Pk, CA 94025 USA

[4] Stanford Univ, Geballe Lab Adv Mat, Stanford, CA 94305 USA

[5] Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA

来源：

PHYSICAL REVIEW B | 2018年 / 97卷 / 14期

基金：

美国国家科学基金会;

关键词：

CHARGE-DENSITY-WAVE; ELECTRON-PHONON MODEL; HOLSTEIN MODEL; TEMPERATURE SUPERCONDUCTOR; INFINITE DIMENSIONS; LATTICE-VIBRATIONS; VERTEX;

D O I：

10.1103/PhysRevB.97.140501

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The superconducting (SC) and charge-density-wave (CDW) susceptibilities of the two-dimensional Holstein model are computed using determinant quantum Monte Carlo, and compared with results computed using the Migdal-Eliashberg (ME) approach. We access temperatures as low as 25 times less than the Fermi energy, E-F, which are still above the SC transition. We find that the SC susceptibility at low T agrees quantitatively with the ME theory up to a dimensionless electron-phonon coupling lambda(0) approximate to 0.4 but deviates dramatically for larger lambda(0). We find that for large lambda(0) and small phonon frequency omega(0) << E-F CDW ordering is favored and the preferred CDW ordering vector is uncorrelated with any obvious feature of the Fermi surface.

引用

页数：5

共 29 条

[1] Breakdown of the Migdal-Eliashberg theory in the strong-coupling adiabatic regime [J].