A novel spin modulation of work function for C adsorbed Cr/Fe(001) metal gate

Zhong, Kehua; Xu, Guigui; Cheng, Yanmin; Tang, Keqin; Chen, Zhigao; Huang, Zhigao

doi:10.1063/1.4766473

Cited by 8 publications

(5 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The electrons which flip their magnetic moments from +µ B to −µ B are those contained in the energy interval around the Fermi level, their number is donated by ∆N. Then, we have [22] ∆N…”

Section: Resultsmentioning

confidence: 99%

“…[13] All calculations were carried out using the Vienna ab initio simulation package, employing the generalized gradient approximation (GGA) of Perdew-Burke-Ernzerhof for the exchange-correlation function. [10,[14][15][16][17][18][19][20][21][22] As Gd is a typical heavy metal, the spinorbit coupling should be considered. The moderate correlation of 3d electrons and the strong correlation of f electrons in Gd require adding an on-site Coulomb interaction U.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Gd doping on the magnetism and work function of Fe_1—xGd_x/Fe (001)

et al. 2014

View full text Add to dashboard Cite

The magnetism and work function Φ of Fe 1−x Gd x /Fe (001) films have been investigated using first-principles methods based on the density functional theory. The calculated results reveal that Gd doping on the Fe (001) surface would greatly affect the geometrical structure of the system. The restruction of the surface atoms leads to the transition of magnetic coupling between Gd and Fe atoms from ferromagnetic (FM) for 0.5 ≤ x ≤ 0.75 to antiferromagnetic (AFM) for x = 1.0. For Fe 1−x Gd x /Fe (001) (x = 0.25, 0.5, 0.75, 1.0), the charge transfer from Gd to Fe leads to a positive dipole formed on the surface, which is responsible for the decrease of the work function. Moreover, it is found that the magnetic moments of Fe and Gd on the surface layer can be strongly influenced by Gd doping. The changes of the work function and magnetism for Fe 1−x Gd x /Fe (001) can be explained by the electron transfer, the magnetic coupling interaction between Gd and Fe atoms, and the complex surface restruction. Our work strongly suggests that the doping of the metal with a low work function is a promising way for modulating the work function of the magnetic metal gate.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Effect of Gd doping on the magnetism and work function of Fe_1—xGd_x/Fe (001)

et al. 2014

View full text Add to dashboard Cite

show abstract

“…In our work, the first-principle calculations were implemented by using Vienna ab initio simulation package (VASP), and the projector augmented wave method was considered in the electron-ion interactions [ 40 , 41 , 42 , 43 , 44 , 45 , 46 ]. The exchange-correlation energy was calculated based on Perdew-Burke-Ernzerhof (PBE) [ 47 ] formulation of generalized gradient approximation (GGA) [ 40 ].…”

Section: Methodsmentioning

confidence: 99%

An Ab Initio and Kinetic Monte Carlo Simulation Study of Lithium Ion Diffusion on Graphene

Zhong

Yang

et al. 2017

Materials

Self Cite

View full text Add to dashboard Cite

The Li+ diffusion coefficients in Li+-adsorbed graphene systems were determined by combining first-principle calculations based on density functional theory with Kinetic Monte Carlo simulations. The calculated results indicate that the interactions between Li ions have a very important influence on lithium diffusion. Based on energy barriers directly obtained from first-principle calculations for single-Li+ and two-Li+ adsorbed systems, a new equation predicting energy barriers with more than two Li ions was deduced. Furthermore, it is found that the temperature dependence of Li+ diffusion coefficients fits well to the Arrhenius equation, rather than meeting the equation from electrochemical impedance spectroscopy applied to estimate experimental diffusion coefficients. Moreover, the calculated results also reveal that Li+ concentration dependence of diffusion coefficients roughly fits to the equation from electrochemical impedance spectroscopy in a low concentration region; however, it seriously deviates from the equation in a high concentration region. So, the equation from electrochemical impedance spectroscopy technique could not be simply used to estimate the Li+ diffusion coefficient for all Li+-adsorbed graphene systems with various Li+ concentrations. Our work suggests that interactions between Li ions, and among Li ion and host atoms will influence the Li+ diffusion, which determines that the Li+ intercalation dependence of Li+ diffusion coefficient should be changed and complex.

show abstract

“…All the calculations were performed using Vienna ab initio simulation package (VASP) with projector augmented wave approach [44][45][46][47][48][49][50]. The exchange correlation energy was calculated using PW91 generalized gradient approximation (GGA) [45].…”

Section: Methodsmentioning

confidence: 99%

Effects of intrinsic defects on effective work function for Ni/HfO2 interfaces

Zhong

Zhang

et al. 2016

Materials Chemistry and Physics

Self Cite

View full text Add to dashboard Cite

The effective work functions and formation energies for Ni/HfO2 interfaces with and without defects, including interfacial intrinsic atom substitution and atom vacancy in interfacial layer were studied by first-principles methods based on density functional theory (DFT). The calculated results of the formation energies indicate that the interfaces with O-Ni combining bonds in the interfacial region are more energetically favorable and a small amount O vacancy is comparatively easy to form in O-Ni interface, especially under O-rich situation. Moreover, the results of our calculations also reveal that, (1) the effective work functions strongly depend on the type of interface, interface roughness and atom substitution content in the interface region;(2) for Hf-Ni interfaces, two calculated effective work functions without and with Ni substitutions in whole interfacial Hf layer are good for nMOS and pMOS effective work function (EWF) engineering, respectively; (3) the EWFs are sensitive to Hf vacancy rather than Ni vacancy in interfacial layer for Hf-Ni interfaces; (4) oxygen vacancies can result in a © 2016. This manuscript version is made available under the Elsevier user license http://www.elsevier.com/open-access/userlicense/1.0/ 2 decrease of effective work function for O-Ni interfaces. Additionally, we establish an expectedtheoretical relationship that variations of the EWFs are in proportion to that of interface dipole density. Finally, ionic valence state and occupied state are used to qualitatively analyze and explain the effects of interfacial defects on the EWF in metal-oxide interfaces. Our work suggests that controlling interfacial intrinsic atom substitution and interface roughness are attractive and promising ways for modulating the effective work function of Ni/HfO2 interfaces. IntroductionTo solve the problems arising from the aggressive size downscaling of metal-oxide-semiconductor field-effect transistor (MOSFET), both high dielectric constant "high-k" gate dielectric and metal gate electrode are required to replace the traditional SiO2 gate dielectric and polycrystalline Si, respectively [1,2]. Because of its high dielectric constant, excellent thermal stability and compatibility with various technical requirements, Hafnium oxide (HfO2) has emerged as one of the most preferred gate oxides in high-k metal gate technology [2-4]. While for desirable metal gate, an appropriate effective work function needs to satisfy the requirement that it lies near the valence and conduction band edges of Si substrate (about 4.1eV and 5.2eV for negative MOS [nMOS] and positive MOS [pMOS], respectively) [5]. There have been many studies [6-16] on tuning the effective work function (EWF) of metal-high-k gate stacks and several accompanying possible modulation methods for the EWF, such as binary 3 alloys [6], bilayer metal gate technology [7], and atomic dopant [8][9][10][11][12][13][14][15]. However, even so, the EWF is difficult to control, especially for pMOS, due to its extreme sensitivity to a number of factors th...

show abstract

A novel spin modulation of work function for C adsorbed Cr/Fe(001) metal gate

Cited by 8 publications

References 47 publications

Effect of Gd doping on the magnetism and work function of Fe_1—xGd_x/Fe (001)

Effect of Gd doping on the magnetism and work function of Fe_1—xGd_x/Fe (001)

An Ab Initio and Kinetic Monte Carlo Simulation Study of Lithium Ion Diffusion on Graphene

Effects of intrinsic defects on effective work function for Ni/HfO2 interfaces

Contact Info

Product

Resources

About

A novel spin modulation of work function for C adsorbed Cr/Fe(001) metal gate

Cited by 8 publications

References 47 publications

Effect of Gd doping on the magnetism and work function of Fe1—xGdx/Fe (001)

Effect of Gd doping on the magnetism and work function of Fe1—xGdx/Fe (001)

An Ab Initio and Kinetic Monte Carlo Simulation Study of Lithium Ion Diffusion on Graphene

Effects of intrinsic defects on effective work function for Ni/HfO2 interfaces

Contact Info

Product

Resources

About

Effect of Gd doping on the magnetism and work function of Fe_1—xGd_x/Fe (001)

Effect of Gd doping on the magnetism and work function of Fe_1—xGd_x/Fe (001)