Wei, CM, Chou MY.
2003.
Effects of the substrate on quantum well states: A first-principles study for Ag/Fe(100), Sep. Physical Review B. 68:5., Number 12
AbstractWe have studied the properties of quantum well states in supported Ag(100) films on the Fe substrate by first-principles density-functional calculations. The energies of these quantum well states as a function of thickness N are examined in terms of the characteristic phase shift of the electronic wave function at the interface. These energy-dependent phase shifts are determined numerically for both the film-substrate and film-vacuum interfaces. It is also found that the substrate has a major effect on film stability, enhancing the stability of the N=5 film and reversing that of the N=2 film.
Wei, CM, Chou MY.
2003.
Effects of the substrate on quantum well states: A first-principles study for Ag/Fe(100), Sep. Physical Review B. 68:5., Number 12
AbstractWe have studied the properties of quantum well states in supported Ag(100) films on the Fe substrate by first-principles density-functional calculations. The energies of these quantum well states as a function of thickness N are examined in terms of the characteristic phase shift of the electronic wave function at the interface. These energy-dependent phase shifts are determined numerically for both the film-substrate and film-vacuum interfaces. It is also found that the substrate has a major effect on film stability, enhancing the stability of the N=5 film and reversing that of the N=2 film.
Alford, JA, Chou MY, Chang EK, Louie SG.
2003.
First-principles studies of quasiparticle band structures of cubic YH3 and LaH3, Mar. Physical Review B. 67:7., Number 12
AbstractQuasiparticle band structures for the cubic trihydrides YH3 and LaH3 have been calculated by evaluating the self-energy in the GW approximation using ab initio pseudopotentials and plane waves. These are the prototype metal hydrides that exhibit switchable optical properties. For both materials, the local-density approximation (LDA) yields semimetallic energy bands with a direct overlap of about 1 eV. We find the self-energy correction to the LDA energies opens a gap at Gamma of 0.8-0.9 eV for LaH3 and 0.2-0.3 eV for YH3, where the latter is in sharp contrast to a previous study using linear-muffin-tin orbitals. The quasiparticle band gaps are analyzed as a function of an initial shift in the LDA bands used to evaluate the random-phase approximation screening in constructing the self-energy. We also make a comparison of results obtained by using two different pseudopotentials, each designed to better approximate exchange and correlation between the semicore states and valence states of Y and La.
Chang, CM, Wei CM.
2003.
Diffusion of an adsorbed Si atom on the Si(111)-(7x7) surface, Jan. Physical Review B. 67:4., Number 3
AbstractWe present first-principles calculations that provide a detailed diffusion picture of an adsorbed Si atom on the Si(111)-(7x7) surface. Several diffusion paths for the adsorbed Si atom are established by mapping out the total energy as a function of its positions on the surface. For diffusion between the faulted and unfaulted halves, the energy barriers range from 0.96 to 1.21 eV, while remarkable low-energy barriers from 0.3 to 0.7 eV are discovered within the faulted and unfaulted regions.
Hong, HW, Wei CM, Chou MY, Wu Z, Basile L, Chen H, Holt M, Chiang TC.
2003.
Alternating layer and island growth of Pb on Si by spontaneous quantum phase separation, Feb. Physical Review Letters. 90:4., Number 7
AbstractReal-time in situ x-ray studies of continuous Pb deposition on Si(111)-(7x7) at 180 K reveal an unusual growth behavior. A wetting layer forms first to cover the entire surface. Then islands of a fairly uniform height of about five monolayers form on top of the wetting layer and grow to fill the surface. The growth then switches to a layer-by-layer mode upon further deposition. This behavior of alternating layer and island growth can be attributed to spontaneous quantum phase separation based on a first-principles calculation of the system energy.
Hong, HW, Wei CM, Chou MY, Wu Z, Basile L, Chen H, Holt M, Chiang TC.
2003.
Alternating layer and island growth of Pb on Si by spontaneous quantum phase separation, Feb. Physical Review Letters. 90:4., Number 7
AbstractReal-time in situ x-ray studies of continuous Pb deposition on Si(111)-(7x7) at 180 K reveal an unusual growth behavior. A wetting layer forms first to cover the entire surface. Then islands of a fairly uniform height of about five monolayers form on top of the wetting layer and grow to fill the surface. The growth then switches to a layer-by-layer mode upon further deposition. This behavior of alternating layer and island growth can be attributed to spontaneous quantum phase separation based on a first-principles calculation of the system energy.
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