Thickness-dependent spontaneous dewetting morphology of ultrathin Ag films

We show here that the morphological pathway of spontaneous dewetting of ultrathin Ag films on SiO2 under nanosecond laser melting is found to be film thickness dependent. For films with thickness h between 2 <= h <= 9.5 nm, the morphology during the intermediate stages of dewetting consisted of bicontinuous structures. For films 11.5 <= h <= 20 nm, the intermediate stages consisted of regularly-sized holes. Measurement of the characteristic length scales for different stages of dewetting as a function of film thickness showed a systematic increase, which is consistent with the spinodal dewetting instability over the entire thickness range investigated. This change in morphology with thickness is consistent with observations made previously for polymer films [A. Sharma et al, Phys. Rev. Lett., v81, pp3463 (1998); R. Seemann et al, J. Phys. Cond. Matt., v13, pp4925, (2001)]. Based on the behavior of free energy curvature that incorporates intermolecular forces, we have estimated the morphological transition thickness for the intermolecular forces for Ag on SiO2 . The theory predictions agree well with observations for Ag. These results show that it is possible to form a variety of complex Ag nanomorphologies in a consistent manner, which could be useful in optical applications of Ag surfaces, such as in surface enhanced Raman sensing.Comment: 20 pages, 5 figure

Gate-Voltage Control of Chemical Potential and Weak Anti-localization in Bismuth Selenide

We report that Bi$_2$Se$_3$ thin films can be epitaxially grown on SrTiO$_{3}$ substrates, which allow for very large tunablity in carrier density with a back-gate. The observed low field magnetoconductivity due to weak anti-localization (WAL) has a very weak gate-voltage dependence unless the electron density is reduced to very low values. Such a transition in WAL is correlated with unusual changes in longitudinal and Hall resistivities. Our results suggest much suppressed bulk conductivity at large negative gate-voltages and a possible role of surface states in the WAL phenomena. This work may pave a way for realizing three-dimensional topological insulators at ambient conditions.Comment: 5 pages, 4 figures

The one-dimensional Hubbard model with open ends: Universal divergent contributions to the magnetic susceptibility

The magnetic susceptibility of the one-dimensional Hubbard model with open boundary conditions at arbitrary filling is obtained from field theory at low temperatures and small magnetic fields, including leading and next-leading orders. Logarithmic contributions to the bulk part are identified as well as algebraic-logarithmic divergences in the boundary contribution. As a manifestation of spin-charge separation, the result for the boundary part at low energies turns out to be independent of filling and interaction strength and identical to the result for the Heisenberg model. For the bulk part at zero temperature, the scale in the logarithms is determined exactly from the Bethe ansatz. At finite temperature, the susceptibility profile as well as the Friedel oscillations in the magnetisation are obtained numerically from the density-matrix renormalisation group applied to transfer matrices. Agreement is found with an exact asymptotic expansion of the relevant correlation function.Comment: 30 pages, 8 figures, reference adde

Quantum criticality and nodal superconductivity in the FeAs-based superconductor KFe2As2

The in-plane resistivity $\rho$ and thermal conductivity $\kappa$ of FeAs-based superconductor KFe$_2$As$_2$ single crystal were measured down to 50 mK. We observe non-Fermi-liquid behavior $\rho(T) \sim T^{1.5}$ at $H_{c_2}$ = 5 T, and the development of a Fermi liquid state with $\rho(T) \sim T^2$ when further increasing field. This suggests a field-induced quantum critical point, occurring at the superconducting upper critical field $H_{c_2}$. In zero field there is a large residual linear term $\kappa_0/T$, and the field dependence of $\kappa_0/T$ mimics that in d-wave cuprate superconductors. This indicates that the superconducting gaps in KFe$_2$As$_2$ have nodes, likely d-wave symmetry. Such a nodal superconductivity is attributed to the antiferromagnetic spin fluctuations near the quantum critical point.Comment: 4 pages, 4 figures - replaces arXiv:0909.485

Air/water interfacial waves with a droplet at the tip of their crest

In nature, it is common to observe water wave crests with a droplet at their tip. This fascinating configuration remains unexplained from the physical point of view. The present study explores such a unique local configuration numerically. Solitary waves that propagate at the interface between two layers of irrotational fluids are considered. Extending the work of Guan et al. [“A local model for the limiting configuration of interfacial solitary waves,” J. Fluid Mech. 921, A9 (2021)], the density ratio has been decreased to a very small value equal to 0.001, which is close to the air/water density ratio at sea level (0.0013). A highly accurate solution for the limiting configuration of solitary waves is obtained by solving the irrotational Euler equations using the boundary integral method and Newton's iterations. It is confirmed that the limiting configuration consisting of a droplet sitting on a crest with a [Formula: see text] angle exists for very small density ratios. This limiting configuration obviously does not exist for surface waves with a void on the top, thus stressing the crucial role played by the air. The droplet is stationary in a frame of reference moving with the wave and experiences intense shear at its tip. From the energy point of view, the formation of a crest with a droplet is accompanied by a remarkable drop of kinetic and potential energies of water in the vicinity of the crest. Furthermore, we present a simple set of scaling relations for the fall of the droplet

The interplay of proactive personality and internship quality in Chinese university graduates' job search success: The role of career adaptability

Based on the job characteristics model and career construction theory, this study examined the role of internship quality in the employment success of Chinese university students. A four-wave survey study was conducted in a sample of university graduates (N = 207) and the results showed that after the effects of baseline career adaptability (Time 1) were controlled, internship quality (Time 2) and proactive personality (Time 2) positively were both associated with subsequent career adaptability (Time 3), which was further related to indicators of employment success (number of job offers, starting salary, and job search efficiency) at Time 4. In addition, internship quality was also found to be a significant moderator of the relationship between proactive personality and career adaptability as well as employment success, such that when internship quality was lower, the indirect effect of proactive personality on job search success through career adaptability was stronger. The corresponding moderated mediation model was also supported by the results. These findings carry implications for future studies on school-to-work transition and organizational recruitment practices

Sale Force Automation Systems: The Correspondence Between The Perception Of Productivity Gains And The Perception Of Management Control Among Salespeople

Sales force automation (SFA) technologies have many apparent benefits, but the adoption of SFA systems often fails because the sales force holds poor perceptions of these technologies. Understanding how these perceptions affect adoption of SFA systems is important because negative perceptions held by the sales force can often adversely influence the successful adoption and implementation of such systems. This paper examines how the sales force’s  perceptions of productivity gains resulting from the adoption of an SFA system can be affected by their corresponding  perception of the SFA system as a tool employed by upper-level management to more closely manage the activities of the sales force. The results are based on a national survey of 1,657 salespeople. The findings indicate a negative relationship between salespeople’s perceptions of the potential gains associated with the adoption of an SFA system and their corresponding perception of the use of the system by upper-level management to more closely manage the activities of the sales force

Sales Force Automation Acceptance: An Exploratory Study Of The Role Of Job Experience

User perceptions of new technologies may ultimately affect their acceptance of that technology. Recent research has identified a clear connection between user perceptions of Sales Force Automation and their acceptance of Sales Force Automation technologies.&nbsp; Anecdotal evidence suggests that relative to less experienced salespeople, more experienced salespeople tend to have more negative perceptions of sales force automation.&nbsp; This paper examines the relationship between job experience and perceptions of a sales force automation system.&nbsp; The results are based on a survey of 1,657 salespeople about their perceptions of several aspects of a sales force automation system in a large sales organization.&nbsp; This study finds significant differences by sales experience in areas such as perceived productivity/efficiency gain, perception of sales force automation as a micromanagement tool, and user satisfaction with system functionality.&nbsp; Based on these results several important managerial implications for the adoption of a sales force automation system are suggested

Integrable variant of the one-dimensional Hubbard model

A new integrable model which is a variant of the one-dimensional Hubbard model is proposed. The integrability of the model is verified by presenting the associated quantum R-matrix which satisfies the Yang-Baxter equation. We argue that the new model possesses the SO(4) algebra symmetry, which contains a representation of the $\eta$-pairing SU(2) algebra and a spin SU(2) algebra. Additionally, the algebraic Bethe ansatz is studied by means of the quantum inverse scattering method. The spectrum of the Hamiltonian, eigenvectors, as well as the Bethe ansatz equations, are discussed