| 1. |
- Singh, A., et al.
(författare)
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Trion formation dynamics in monolayer transition metal dichalcogenides
- 2016
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Ingår i: Physical Review B. - 2469-9969 .- 2469-9950. ; 93:4
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Tidskriftsartikel (refereegranskat)abstract
- We report charged exciton (trion) formation dynamics in doped monolayer transition metal dichalcogenides, specifically molybdenum diselenide (MoSe2), using resonant two-color pump-probe spectroscopy. When resonantly pumping the exciton transition, trions are generated on a picosecond time scale through exciton-electron interaction. As the pump energy is tuned from the high energy to low energy side of the inhomogeneously broadened exciton resonance, the trion formation time increases by ∼50%. This feature can be explained by the existence of both localized and delocalized excitons in a disordered potential and suggests the existence of an exciton mobility edge in transition metal dichalcogenides.
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| 2. |
- Nascimento, V. B., et al.
(författare)
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Procedure for LEED I-V structural analysis of metal oxide surfaces : Ca1.5Sr0.5RuO4(001)
- 2007
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 75:3, s. 035408-
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Tidskriftsartikel (refereegranskat)abstract
- Transition metal oxides (TMOs) are famous for the intimate coupling between the lattice, electrons, and spin, creating exotic functionality. Creating a surface, breaking the symmetry, should result in lattice distortions that due to the close coupling could create different "surface phases." Historically it has been very difficult to use low energy electron diffraction I-V to quantitatively determine the surface structure of TMOs. A signature of this problem is the large values commonly reported in the literature of the Pendry reliability factor (R-P), which is used to quantify the agreement between experimental data and calculated diffraction. In this paper we describe a consistent procedure for determining the phase shifts using an optimized muffin-tin potential approach combined with an energy-dependent real and imaginary inner potential. This procedure is used to determine the surface structure of the layered TMO Ca1.5Sr0.5RuO4. An acceptable Pendry reliability factor is achieved (R-P=0.28).
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| 3. |
- Moore, R. G., et al.
(författare)
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Manifestations of broken symmetry : The surface phases of Ca2-xSrxRuO4
- 2008
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 100:6, s. 066102-
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Tidskriftsartikel (refereegranskat)abstract
- The surface structural phases of Ca2-xSrxRuO4 are investigated using quantitative low energy electron diffraction. The broken symmetry at the surface enhances the structural instability against the RuO6 rotational distortion while diminishing the instability against the RuO6 tilt distortion occurring within the bulk crystal. As a result, suppressed structural and electronic surface phase transition temperatures are observed, including the appearance of an inherent Mott metal-to-insulator transition for x=0.1 and possible modifications of the surface quantum critical point near x(c)similar to 0.5.
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