title: Strain effects on work functions of pristine and potassium-decorated carbon nanotubes.
abstract: Strain dependence of electronic structures and work functions of both pristine and potassium doped (5,5) (armchair) and (9,0) (zigzag) carbon nanotubes (CNTs) has been thoroughly studied using first-principles calculations based on density functional theory. We found that for pristine cases, the uniaxial strain has strong effects on work functions of CNTs, and the responses of work functions of CNT (5,5) and (9,0) to the strain are distinctly different. When the strain changes from -10% to 10%, the work function of the CNT (5,5) increases monotonically from 3.95 to 4.57 eV, and the work function of the (9,0) varies between 4.27 and 5.24 eV in a complicated manner. When coated with potassium, for both CNTs, work functions can be lowered down by more than 2.0 eV, and the strain dependence of work functions changes drastically. Our studies suggested that the combination of chemical coating and tuning of strain may be a powerful tool for controlling work functions of CNTs, which in turn will be useful in future design of CNT-based electronic and field-emitting devices.
authors.affiliation: Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore.
authors.forename: Cai
authors.initials: C
authors.lastname: Yongqing
authors.forename: TheYongqing
authors.initials: T
authors.lastname: Cai
authors.forename: Aihua
authors.initials: A
authors.lastname: Zhang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Ping Feng
authors.forename: Chun
authors.initials: C
authors.lastname: Zhang
authors.forename: Hao
authors.initials: H
authors.lastname: Fatt Teoh
authors.forename: Ghim
authors.initials: G
authors.lastname: Wei Ho