Charge transfer and electron-phonon coupling in monolayer FeSe on Nb-doped SrTiO3

被引：38

作者：

Zhou, Yuanjun ^{[1
]}

Millis, Andrew J. ^{[1
]}

机构：

[1] Columbia Univ, Dept Phys, 538 W 120th St, New York, NY 10027 USA

来源：

PHYSICAL REVIEW B | 2016年 / 93卷 / 22期

基金：

美国国家科学基金会;

关键词：

AUGMENTED-WAVE METHOD; IRON CHALCOGENIDES; THIN-FILMS; SUPERCONDUCTIVITY;

D O I：

10.1103/PhysRevB.93.224506

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Monolayer films of FeSe grown on SrTiO3 substrates are electron doped relative to bulk and exhibit a significantly higher superconducting transition temperature. An interaction of electrons in the FeSe layer with SrTiO3 phonons has been suggested. We present density functional calculations and a modified Schottky model incorporating the strong paraelectricity of SrTiO3, which demonstrate that the doping may be due to charge transfer from SrTiO3 impurity bands driven by work-function mismatch. Physically relevant levels of Nb doping are shown to lead to doping of the FeSe compatible with observation. The coupling of electrons in FeSe to polar phonons in the depletion region of the SrTiO3 is calculated. An electron-phonon coupling strength lambda = -partial derivative Re Sigma/partial derivative omega vertical bar(omega=0) similar to 0.4 is found; the coupling to long-wavelength phonons is found to be dominant.

引用

页数：8

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