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Due to the coexistence of Dirac and triplet fermions, monolayer β12-borophene has recently attracted both experimental and theoretical researchers. In particular, various phase transitions have been recently reported in the structure, in the presence of dilute charged impurity and a perpendicular electric field, leading to interesting electronic heat capacity (HC). In this paper, we systematically examine the effects of charged impurity doping and electric field on the HC of monolayer β12-borophene. To do this, we utilize the five-band tight-binding Hamiltonian model, the Green's function, T-matrix, and the Born approximation for different models considering the substrate effects. Numerical analysis reveals that the inversion symmetric model is the proper model in the pristine and perturbed metallic β12-borophene, leading to a regular reduction of HC with both charged impurity and electric field. Moreover, the pristine and perturbed Schottky anomaly alterations are fully addressed. Unforeseeably, HC irregularly fluctuates with impurity in the homogeneous model. We believe that our results provide new physical insights into the thermal properties of monolayer β12-borophene.

β12-Borophene is a perfect planar nanolattice comprising of massless Dirac fermions and massless/massive triplet fermions considering the inversion symmetry lattice model. In this paper, a detailed study of the electric field and the effects of low concentrations of impurities on the electronic phase and the electrical conductivity of β12-borophene is presented. As a direct manner to judge the electronic features of pristine and perturbed monolayer β12-borophene, the five-band tight-binding Hamiltonian model, the T-matrix theory, the linear response theory, and the Green's function approach are investigated. Our investigation reveals that the massless Dirac and triplet fermions become massive when an electric field is applied. Also, we found out that the electric current and eventually the electrical conductivity are not the same along different directions and an enhancement of around 18.53% (15.38%) for the x-direction (in-plane) component is observed at a certain thermal energy. Furthermore, the metal-to-semiconductor electronic phase transition in the presence of different impurity atoms results in a 197.16% (198.23%) enhancement in x- (in-plane-) component of electrical conductivity. The results provide a basis of designing novel electronic devices based on β12-borophene.

In this paper, the potential of engineering and manipulating the electronic heat capacity and Pauli susceptibility of pristine and perturbed hydrogenated AA-stacked graphene, SiC (silicon carbide), and h-BN (hexagonal boron nitride) bilayers is studied using a designed transverse Zeeman magnetic field and the dilute charged impurity. The tight-binding Hamiltonian model, the Born approximation and the Green's function method describe the carrier dynamics up to a certain degree. The unperturbed results show that the heat capacity and susceptibility of all bilayers increase with different hydrogenation doping configurations. We also found that the maximum heat capacity and susceptibility relates to the chair-like and table-like configurations. Also, the graphene possesses the highest activity compared to SiC and h-BN lattices due to its zero on-site energies. For the Zeeman magnetic field-induced Schottky anomaly and the Néel temperature corresponding to the maximum electronic heat capacity, EHC Max. , and Pauli spin paramagnetic susceptibility, PSPS Max. , respectively, the pristine EHC Max. (PSPS Max. ) decreases (increases) with the Zeeman field. On the other hand, the corresponding results for reduced table-like and reduced chair-like lattices illustrate that both EHC Max. and PSPS Max. decrease with the Zeeman field, on average. However, under the influence of the dilute charged impurity, the pristine EHC Max. of graphene (SiC and h-BN) decreases (increases) with impurity concentration for all configurations while the corresponding PSPS Max. fluctuates (decreases) for the pristine (reduced table-like and reduced chair-like) case. These findings introduce hydrogenated AA-stacked bilayers as versatile candidates for real applications., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Optical activity is one of the most fascinating fields in current physics. The strong anisotropic feature in monolayer phosphorene leads to the emergence of non-trivial optoelectronic physics. This paper is devoted to a detailed analysis of strain effects on the optical activity of phosphorene ranging from low-optical-field to high-optical-field. To do so, a numerical study of the two-band tight-binding model is accomplished using the Harrison rule and the linear response theory. Although the transparency of phosphorene confirms at all frequencies independent of the strain modulus and direction, on average, from low- to high-optical-field limit, the polarization of the reflected wave at critical strains becomes circular and the ellipse axis tends to a rotation of 180°. It is found that the maximum absorption takes place at high-energy transitions, which quantitatively depends strongly on the strain modulus and direction. Furthermore, a detailed investigation of compressive and tensile strains results in the dominant contribution of the in-plane compressive and out-of-plane tensile strains to the reflected/transmitted light for low- and intermediate-optical-field ranges, whilst both contribute for the high-optical-field limit. However, overall, in-plane compressive and out-of-plane tensile strains come in to play a role in the absorption spectra. Thereby, the quality of the determined reflection, transmission and absorption waves depends on the regarded regime of the optical field, strain modulus, and strain orientation. These findings if sufficient can be performed and/or tuned experimentally, and a vast number of phosphorene-based optoelectronic devices can be achieved., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)