Photoemission Study of K Doping on a Monolayer of C60 on Clean Si(001)-(2 × 1) Surface

1998 ◽  
Vol 05 (01) ◽  
pp. 101-104 ◽  
Author(s):  
Tun-Wen Pi ◽  
Le-Hong Hong ◽  
Rong-Tzong Wu ◽  
Chiu-Ping Cheng ◽  
May-Ho Ko
Keyword(s):  
Binding Energy ◽  
Work Function ◽  
Valence Band ◽  
Weak Interaction ◽  
Silicon Surface ◽  
Many Body ◽  
Body Effect ◽  
Charge Polarization ◽  
The Many ◽  
Photoemission Study

We present the first valence band photoemission study of a monolayer K x C 60 on a clean Si(001)-(2 × 1) surface. The monolayer C60 which shows weak interaction with the silicon surface reveals clear, but broadened, structures corresponding to bulk C 60. Upon K exposure, the work function drops rapidly due to charge polarization toward the Si surface, considerably affecting then the rate of the Lumo filling. Its centroid initially shown at 0.6 eV shifts to higher binding energy with higher concentration. Moreover, the LUMO always separates 1.5 ± 0.1 eV from the Homo. Features associated with the many-body effect do not appear in the spectra. The Fermi cutoff has never been observed, indicating the insulating nature of the K x C 60 surface.

scholarly journals Surface chemistry effects on work function, ionization potential and electronic affinity of Si(100), Ge(100) surfaces and SiGe heterostructures

2020 ◽  
Vol 22 (44) ◽  
pp. 25593-25605
Author(s):  
Ivan Marri ◽  
Michele Amato ◽  
Matteo Bertocchi ◽  
Andrea Ferretti ◽  
Daniele Varsano ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Surface Chemistry ◽  
Work Function ◽  
Ionization Potential ◽  
Many Body ◽  
Many Body Perturbation Theory ◽  
The Many ◽  
Electronic Affinity

Surface chemistry effects are calculated within the many body perturbation theory for Si(100), Ge(100) and SiGe surfaces.

scholarly journals Tunable discrete scale invariance in transition-metal pentatelluride flakes

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Yanzhao Liu ◽  
Huichao Wang ◽  
Haipeng Zhu ◽  
Yanan Li ◽  
Jun Ge ◽  
...  
Keyword(s):  
Transition Metal ◽  
Scale Invariance ◽  
Bound States ◽  
Scale Factor ◽  
Coulomb Interactions ◽  
Many Body ◽  
Body Effect ◽  
Discrete Scale Invariance ◽  
The Many ◽  
Discrete Scale

AbstractLog-periodic quantum oscillations discovered in transition-metal pentatelluride give a clear demonstration of discrete scale invariance (DSI) in solid-state materials. The peculiar phenomenon is convincingly interpreted as the presence of two-body quasi-bound states in a Coulomb potential. However, the modifications of the Coulomb interactions in many-body systems having a Dirac-like spectrum are not fully understood. Here, we report the observation of tunable log-periodic oscillations and DSI in ZrTe5 and HfTe5 flakes. By reducing the flakes thickness, the characteristic scale factor is tuned to a much smaller value due to the reduction of the vacuum polarization effect. The decreasing of the scale factor demonstrates the many-body effect on the DSI, which has rarely been discussed hitherto. Furthermore, the cut-offs of oscillations are quantitatively explained by considering the Thomas-Fermi screening effect. Our work clarifies the many-body effect on DSI and paves a way to tune the DSI in quantum materials.

An adaptive quantum mechanics/molecular mechanics method for the infrared spectrum of water: incorporation of the quantum effect between solute and solvent

2016 ◽  
Vol 18 (10) ◽  
pp. 7318-7333 ◽  
Author(s):  
Hiroshi C. Watanabe ◽  
Misa Banno ◽  
Minoru Sakurai
Keyword(s):  
Quantum Mechanics ◽  
Liquid Phase ◽  
Quantum Effect ◽  
Critical Factors ◽  
Many Body ◽  
Body Effect ◽  
Solvent Interactions ◽  
Factors Influencing ◽  
Induced Dipole ◽  
The Many

Quantum effects in solute–solvent interactions, such as the many-body effect and the dipole-induced dipole, are known to be critical factors influencing the infrared spectra of species in the liquid phase.

Role of the valence-band mass on the many-body optical properties of a two-dimensional electron gas

1998 ◽  
Vol 249-251 ◽  
pp. 603-606
Author(s):  
H.P van der Meulen ◽  
J Rubio ◽  
J.M Calleja ◽  
C Tejedor ◽  
F Rodriguez ◽  
...  
Keyword(s):  
Optical Properties ◽  
Valence Band ◽  
Electron Gas ◽  
Two Dimensional ◽  
Dimensional Electron ◽  
Many Body ◽  
Two Dimensional Electron Gas ◽  
Dimensional Electron Gas ◽  
The Many

VALENCE-BAND PHOTOEMISSION STUDY OF (Ba, Cs) on W(110)

1997 ◽  
Vol 04 (06) ◽  
pp. 1197-1201 ◽  
Author(s):  
TUN-WEN PI ◽  
LE-HONG HONG ◽  
RONG-TZONG WU ◽  
CHIU-PING CHENG
Keyword(s):  
Work Function ◽  
Valence Band ◽  
High Surface ◽  
Surface States ◽  
Metal Substrate ◽  
Inverse Photoemission ◽  
Interfacial Electronic Structure ◽  
Band Spectra ◽  
Photoemission Study ◽  
Tungsten Substrate

We present the first valence-band photoemission study of Ba and Cs on an atomically clean W(110) surface. The cleanness of the tungsten substrate can be justified from both high surface 4f core emission and sharp surface states in the valence-band spectra. Upon Ba (Cs) adsorption, the work function is lowered to 2.02 (1.76) eV, corresponding to one third of a monolayer. Further, the two symmetric high-lying surface states move little in energy but quench rapidly in intensity and diminish at the work-function minimum. On the other hand, the low-lying surface state at 1.41 eV shifts about 215 meV toward higher binding energy and reduces its emission at thicker coverage. The bonding of the Ba d orbital with the W d-like surface states is not found, in contrast to the theoretical calculation and angle-resolved inverse photoemission study of Ba on W(100) . From the coverage-dependent interfacial electronic structure and the parallel behaviors manifest in both Ba on W and Cs on W , the polarized-covalent model for the alkali-metal–substrate interactions is firmly reinforced.

EXPERIMENTAL EVIDENCE OF ITINERANT Cu 3d9 - OXYGEN HOLE MANY BODY CONFIGURATION IN THE HIGH-TC SUPERCONDUCTOR YBa2Cu3O~7

1987 ◽  
Vol 01 (03n04) ◽  
pp. 853-862 ◽  
Author(s):  
A. Bianconi ◽  
A. Clozza ◽  
A. Congiu Castellano ◽  
S. Della Longa ◽  
M. De Santis ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Many Body ◽  
Initial State ◽  
Edge Structure ◽  
Xps Spectra ◽  
X Ray ◽  
Oxygen Hole ◽  
The Many

Cu L3 x-ray absorption near edge structure (XANES) and Cu L 3 x-ray photoelectron spectroscopy (XPS) of YBa2Cu3O6.5+x are compared. The breakdown of one-electron picture of its electronic structure is reported. The data are interpreted by mixing of Cu 3d9 and of [Formula: see text] (where [Formula: see text] is a hole in the oxygen derived band, ligand hole) many body configuration in the initial state. The localization of Cu 3d9 configuration is indicated by the bare Coulomb interaction Udd~6 eV . The conductivity is assigned to the itinerant [Formula: see text] configuration. The experimental evidence that the additional oxygen x, giving higher Tc , increases the weight of the [Formula: see text] configuration is reported. The presence of holes on the oxygen atoms is confirmed by the Ols XPS spectra. The Cu3+(Cu 3d8) configuration is not observed in L3 XANES in agreement with valence band XPS giving the energy of the 3d8 excited state at about 12 eV above the ground state. An energy scheme of the many body configurations in YBa2Cu3O~7 is obtained. These experiments give experimental evidence that the high Tc superconductivity is due to pairing of holes in the oxygen valence band interacting with localized electrons at the Cu sites.

scholarly journals Biexcitons in 2D (iso-BA)2PbI4 perovskite crystals

Nanophotonics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 2001-2006 ◽  
Author(s):  
Wancai Li ◽  
Jiaqi Ma ◽  
Haizhen Wang ◽  
Chen Fang ◽  
Hongmei Luo ◽  
...  
Keyword(s):  
Binding Energy ◽  
Three Dimensional ◽  
Excitation Power ◽  
Environmental Stability ◽  
Excitation Power Density ◽  
Many Body ◽  
Storage Devices ◽  
Photoelectric Properties ◽  
Biexciton Binding Energy ◽  
The Many

AbstractTwo-dimensional (2D) organic-inorganic hybrid perovskites have attracted growing attention recently due to their naturally formed quantum-well structure, unique photoelectric properties and better environmental stability compared to three-dimensional perovskites. The reduced screening and enhanced Coulomb interaction in 2D perovskites result in the formation of excitonic complexes. While the properties of free excitons have been well investigated, studies on biexcitons remain elusive. Here, we report on the biexcitons in 2D (iso-BA)2PbI4 (BA=C4H9NH3) crystals. The biexciton emission can be observed under a very low excitation power density of 6.4 W/cm2 at 78 K. The biexciton exhibits a large biexciton binding energy of 46 meV due to the large exciton binding energy of (iso-BA)2PbI4. Furthermore, the biexcitons exhibit a favorable polarization orientation, resulting in different anisotropy between biexcitons and excitons. Our findings would motivate more studies on biexcitons in 2D perovskites and pave the way for exploiting the many-body physics for biexciton lasing and optical storage devices.

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