Monte Carlo analysis of phosphorene nanotransistors

Many-body quantum Monte Carlo study of 2D materials: cohesion and band gap in single-layer phosphorene

Quantum Monte Carlo (QMC) is applied to obtain the fundamental (quasiparticle) electronic band gap, $Δ_f$, of a semiconducting two-dimensional (2D) phosphorene whose optical and electronic properties fill the void between graphene and 2D transition metal dichalcogenides. Similarly to other 2D materials, the electronic structure of phosphorene is strongly influenced by reduced screening, making it challenging to obtain reliable predictions by single-particle density functional methods. Advanced GW techniques, which include many-body effects as perturbative corrections, are hardly consistent wit…

Room temperature magnetism on the zigzag edges of phosphorene nanoribbons

Searching for room temperature ferromagnetic semiconductors has evolved into a broad field of material science and spintronics for decades, nevertheless, these novel states remain rare. Phosphorene, a monolayer black phosphorus with a puckered honeycomb lattice structure possessing a finite band gap and high carrier mobility, has been synthesized recently. Here we show, by means of two different large scale quantum Monte-Carlo methods, that relatively weak interactions can lead to remarkable edge magnetism in the phosphorene nanoribbons. The ground state constrained path quantum Monte-Carlo si…

Effects of low-dimensional material channels on energy consumption of Nano-devices

It is commonly believed that the significant energy saving advantages are belonged to the logic circuits which operate at low temperature as less enegy is needed for cooling them to the treshold temperature after operation. Also, nanoscale thermal management, efficient energy usage in nanoscale and especially thermal optimization are the most challenging issues, while dealing with the new generation of transistors as the miniaturizing unlimitedly the silicon channels of the transistors has resulted in an increase in the energy consumption of computers and the leakage currents. In this paper, t…

Excitonic effects in two-dimensional semiconductors: Path integral Monte Carlo approach

One of the most striking features of novel 2D semiconductors (e.g., transition metal dichalcogenide monolayers or phosphorene) is a strong Coulomb interaction between charge carriers resulting in large excitonic effects. In particular, this leads to the formation of multi-carrier bound states upon photoexcitation (e.g., excitons, trions and biexcitons), which could remain stable at near-room temperatures and contribute significantly to optical properties of such materials. In the present work we have used the Path Integral Monte Carlo methodology to numerically study properties of multi-carrie…

Hydrodynamic signatures in thermal transport in devices based on 2D materials: an ab initio study

We investigate the features arising from hydrodynamic effects in graphene and phosphorene devices with finite heat sources, using ab initio calculations to go beyond Callaway's model and inform a full linearized scattering operator, and solving the phonon Boltzmann transport equation through energy-based deviational Monte Carlo methods. We explain the mechanisms that create those hydrodynamic features, showing that boundary scattering and the relation of sample dimensions to the nonlocal length are the determinant factors, regardless of the relative importance of normal versus resistive scatte…

新型 MoSi$_2$N$_4$/WSi$_2$N$_4$ 场效应晶体管可靠性的研究：蒙特卡洛模拟

An investigation into the reliability of newly proposed MoSi$_2$N$_4$/WSi$_2$N$_4$ field-effect transistors: A monte carlo study

通过蒙特卡洛声子模拟评估新型MoSi$_2$N$_4$/WSi$_2$N$_4$场效应晶体管的热可靠性，发现WSi$_2$N$_4$峰值温度仅110K，优于蓝磷烯，是更可靠的沟道候选材料。