SearcharxivSearch

arXiv · 2311.01285

Controlling high-harmonic generation from strain engineered monolayer phosphorene

Abstract

Phosphorene, a well-studied 2D allotrope of phosphorus, features unique properties such as widely tunable bandgap, high carrier mobility, and remarkable intrinsic in-plane anisotropy. Utilizing these structural and electronic properties, we investigate ultrafast electron dynamics and high harmonic generation (HHG) from phosphorene subject to band structure engineering through external strain, based on ab initio time-dependent density-functional theory approach. We show that strong field processes in such systems can be optimized and controlled by biaxial tensile and compressive strain engineering, that results in electronic structure modification. While -10% strain resulted in closing of band gap, 2% strain increased the gap by 22% with respect to 0.9 eV in pristine phosphorene, consequently affecting the high harmonic yield. With reduction of gap, by applying strain from 2% to -10%, the valence band near $\Gamma-$point becomes more flat and discreet, resulting in large electronic density of states and enhanced electronic excitation, which reflects in their ultrafast sub-cycle dynamics under laser excitation. Moreover, due to its intrinsic in-plane anisotropy, harmonic yield with laser polarization along the armchair (AC) direction is found to be higher than that of the zigzag (ZZ) direction for all the strain cases. Nearly, an order of magnitude enhancement of harmonic intensity is achieved for -10% strain along AC direction. The current study expands the research possibilities of phosphorene into a previously unexplored domain, indicating its potential for future utilization in extreme-ultraviolet and attosecond nanophotonics, and also for efficient table-top HHG sources.

Explore related subjects

Keep this discovery

BibTeXRIS

Saibabu Madas, Subhendu Kahaly, Mousumi Upadhyay Kahaly. 2023-11-02. Controlling high-harmonic generation from strain engineered monolayer phosphorene. https://arxiv.org/abs/2311.01285

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Measuring chiral phonons

Chiral phonons are quantized vibrations where the atomic motion in a solid breaks improper rotation symmetries. In many cases, chiral phonons possess angular momenta and are therefore selective to circularly polarized light. Both fundamental and applied research efforts on chiral phonons have been gaining increasing attention owing to their importance in a variety of fields including spintronics, spin-selective chemical reactions, thermal transport, quantum information processing and biosensing, where the bi-directional spin-lattice coupling enabled by chiral phonons can be harnessed in new ways, and potentially lead to new functionalities. Thus far, the studies of chiral phonons across diverse materials platforms have evolved largely independently within these fields, but the experimental techniques are often interrelated. In this perspective, we present a detailed description, as well as advantages and disadvantages of the current approaches for experimentally measuring chiral phonons in chiral and achiral materials. We conclude with a discussion of new methods for measuring chiral phonons. Ultimately, this work seeks to offer an experimental guide for systematically investigating the properties of chiral phonons in various materials systems and applications.

cond-mat.mtrl-sci

A model of grain growth in UN integrating molecular dynamics, phase-field modeling, and uncertainty quantification

Grain growth kinetics and grain-boundary (GB) properties in uranium mononitride (UN) are investigated through an integrated multiscale framework combining molecular dynamics (MD), phase-field modeling, and surrogate-assisted uncertainty quantification. MD simulations yield GB energies for 27 symmetric tilt boundaries from 0--2000~K, which are consistent with available DFT values. The average GB energy is nearly temperature-independent below 1000~K and increases at higher temperatures. A mechanistic pore-drag model applied to the only available grain growth dataset for actinide nitrides yields a mobility reduction factor of $s \approx 0.93$--$0.99$, statistically indistinguishable from unity, confirming that pore drag is negligible under the experimental conditions. The intrinsic GB mobility is therefore extracted directly from the effective mobility, yielding $M_0 = 2.05\times10^{-15}$~m$^4$/(J$\cdot$s) and $Q_M = 0.89$~eV. Phase-field simulations conducted from 1500--2000~K confirm normal curvature-driven grain growth, with grain size distributions converging to the Hillert-like form. A surrogate-assisted global sensitivity analysis---combining principal component analysis, Gaussian process regression, and Sobol decomposition---reveals that the mobility prefactor $M_0$ dominates output variance at all times, followed by the activation energy $Q_M$, while the GB energy $\gamma$ contributes minimally. These results establish the first quantitative grain growth framework for UN and identify the reduction of uncertainty in $M_0$ and $Q_M$ as the highest-priority target for future experimental efforts.

cond-mat.mtrl-sci

Silicon Solar Cell Design for >30% Efficiency via Singlet Fission

Singlet fission (SF) materials convert high-energy photons into multiple charge carriers, providing a route to exceed the efficiency limits of single-junction silicon solar cells without many of the complexities of multi-junction tandem designs. Following the first demonstration of an SF-enhanced silicon solar cell in 2025, there is a need to understand how SF materials can be effectively integrated into high-efficiency industrial silicon devices and translated from proof of concept to a manufacturable technology. Using coupled optical and electrical simulations, we assess the efficiency potential of several industrially relevant silicon cell architectures combined with SF materials. Interdigitated back-contact (IBC) cells offer the greatest potential for improvement due to unrestricted front-surface access and can achieve efficiencies exceeding 33%. However, performance is highly sensitive to front-surface passivation quality. Appropriate silicon design, particularly controlled surface doping and fixed interfacial charge, can mitigate recombination losses and relax passivation requirements for ultra-thin exciton-transfer layers.

cond-mat.mtrl-sci