Negative Differential Resistance Phenomenon Research Articles

Density functional theory study of the electronic and optical properties of pentagraphyne nanotubes.

Pentagraphyne (PG-yne), a recently predicted two-dimensional (2D) carbon allotrope with appealing properties, has opened up possibilities for a wide range of applications. In this study, we investigate the structural, electronic, optical, and electrical transport properties of a novel one-dimensional (1D) system called pentagraphyne nanotubes (PG-yneNTs), formed by rolling a PG-yne sheet, using density functional theory (DFT) calculations. We design PG-yneNTs with diameters ranging from 6.94 Å to 13.62 Å and employ state-of-the-art theoretical calculations to confirm their energetic, dynamic, and thermodynamic stability. Our electronic band structure calculations reveal that all these nanotubes are wide indirect band gap semiconductors. Remarkably, PG-yneNTs exhibit superior optical properties, including high absorption coefficients and absorption spectra covering the visible regime of the electromagnetic spectrum, making them potential candidates for visible-light-driven photocatalysis and solar cells. Interestingly, both the electronic and optical band gaps increase with the diameter of the nanotubes. Additionally, the observation of negative differential resistance (NDR) phenomena in (4, 0) PG-yneNT suggests their potential applications in NDR devices such as fast switches, frequency multipliers, and memory devices.

Junctionless Negative-Differential-Resistance Device Using 2D Van-Der-Waals Layered Materials for Ternary Parallel Computing.

Negative-differential-resistance (NDR) devices offer a promising pathway for developing future computing technologies characterized by exceptionally low energy consumption, especially multivalued logic computing. Nevertheless, conventional approaches aimed at attaining the NDR phenomenon involve intricate junction configurations and/or external doping processes in the channel region, impeding the progress of NDR devices to the circuit and system levels. Here, an NDR device is presented that incorporates a channel without junctions. The NDR phenomenon is achieved by introducing a metal-insulator-semiconductor capacitor to a portion of the channel area. This approach establishes partial potential barrier and well that effectively restrict the movement of hole and electron carriers within specific voltage ranges. Consequently, this facilitates the implementation of both a ternary inverter and a ternary static-random-access-memory, which are essential components in the development of multivalued logic computing technology.

The Effect of Temperature on a Single-Electron Transistor I-V Curve

In this paper, the effect of temperature on Single-Electron Transistor (SET) electrical behavior is investigated. In particular, a study of the current-voltage (I-V) curves according to parameter (temperature and gate voltage) variation is presented. Among others, the interesting phenomenon of the N-type negative differential resistance is reported as the temperature increases from absolute zero (0 K) to room temperature. Finally, theoretical analysis and simulation shows that the choice of the appropriate temperature and gate-voltage combination the SET I-V curves demonstrates either a negative differential resistance region, a switching effect, or a simple resistance behavior.

Energy-Band Engineering By Remote Doping of Self-Assembled Monolayers Leads to High-Performance Igzo/P-Si Heterostructure Photodetectors

Advancements in emerging technologies, such as autonomous driving, artificial intelligence, medical imaging, and augmented reality, have increased the demand for high-resolution image sensors to transmit further accurate color information. To meet the performance requirements of these applications, several research have been accelerating towards the utilization of emerging low-dimensional semiconductor materials, such as metal oxides, transition metal dichalcogenides, perovskites, and other organic materials.Among them, metal oxide semiconductors (MOSs) are potential candidates for developing high-performance photodetectors. It can be synthesized over large areas using a simple/low-temperature process and are compatible with conventional fabrication equipment. However, MOS-based photodetectors still have several limitations, 1) the presence of charge traps and operational instability on the oxide surface, which degrade photodetection performance, and 2) the absence of an appropriate doping technique for MOS has blocked to improve photodetection performance via materials characteristic modification method.In this study, we present a strategy to overcome these limitations and significantly enhance the performance of IGZO, which is representative of oxide semiconductor thin film, based photodetector with high operation stability and sustainability under ambient atmospheres. We utilized energy-band engineering through an octadecylphosphonic acid (ODPA) self-assembled-monolayer (SAM)-based doping treatment to enhance the photoelectric characteristics of IGZO/p-Si hetero-interfaced devices (ISH). The ODPA consists of a head group of the hydroxyl group, which forms the self-assembled covalent bond formation of R–P–O–substrate. Combining the ODPA SAM with the oxide surface of IGZO provided carrier concentration control based on their a dipole effect, and remain the performance and functionality through the surface encapsulation. As a result, under a light-emitting diode (LED) wavelength with an intensity of 3.9 mW, the proposed device exhibited remarkable photo-switching current ratio of 4.33 × 103 A/A and negative differential resistance (NDR) phenomenon. Espacially, the dark current of the ODPA treated ISH is decreased about 10 times lower than as-fabricated ISH, which shows the possibility of signal noise minimization. These performance improvement is expected to be derived from band properties modulation through IGZO layer annealing and ODPA doping. To clarify the doping effect of each treatment, we characterized the ODPA self-assembled monolayer using X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and Kelvin probe force microscopy (KPFM) to provide comprehensive analysis of the heterointerface effects. We also characterized the electrical properties of IGZO thin-film transistors (TFTs) based on variations of the annealing temperature to clarify the ODPA doping effect.We evaluated 156 ODPA-treated IGZO/p-Si heterostructure photodetectors, which were scaled for fabrication on a 4 inch wafer. The devices exhibited a 100% yield, and uniform current behavior in the dark state (0.20 ± 0.06 nA) and light state (0.87 ± 0.15 µA), owing to an evenly deposited IGZO layer and a simple-to-treat ODPA doping scheme. Furthermore, consecutive sweeps of 20,000 cycles verified excellent cycle-to-cycle endurance, resulting in highly robust photoelectric behaviors without operational failure. Additionally, the performance of the ODPA-treated, IGZO/p-Si heterostructure photodetector remained unchanged for 237 days without degradation under atmospheric exposure (relative humidity (RH) = 37–53 % and 20.6–23.1 °C). Acknowledgements This research was supported by funding supports from the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (NRF-2020R1A2C1101647) and Korea government (MEST) (NRF-2017R1A2B3011222). Figure 1

Regulation of negative differential resistance behavior of zigzag GeSe nanoribbon by the doping of N atoms and edge passivation

Using the first-principles calculations based on density-functional-theory (DFT) combined with nonequilibrium Green functions (NEGF), the electronic structure and transport properties of N-doped zigzag germanium selenide nanoribbon (ZGeSeNR) with different edge passivation atoms are systematically investigated. The calculated numerical results demonstrate the edge passivation atom exert a slight influence on the electronic properties of the N-doped ZGeSeNR. In contrast, the doping position of N atom has a great influence on the band structure of ZGeSeNR. Further, the current-voltage curves of N-doped ZGeSeNR based device exhibit a negative differential resistance (NDR) phenomenon. Moreover, the peak of NDR behavior enters the low bias region when the doping concentration of N atom is reduced to 0.925%, and the peak-valley ratio (PVR) ups to 107. These results are very helpful for the future development of high-performance and low-power electronic devices based on the N-doped ZGeSeNR.

High temperature UV photodetectors based on the negative differential resistance effect of WO3/diamond PN junctions

A positive-negative (PN) junction tunneling diode ultraviolet (UV) photodetector of p-boron-doped diamond (BDD)/n-WO3 nanorods (NRs) with broad-band and good thermal stability was fabricated using heavily boron-doped degenerate semiconductor diamond (BDD) as a substrate. The operating temperature of the p-BDD/n-WO3 photodetector was increased to 300 °C through the negative differential resistance effect, benefiting from the excellent properties of diamond such as an increase in the concentration of boron atoms, a wideband gap (∼5.5 eV), and high thermal conductivity. In particular, the devices exhibited a negative differential resistance phenomenon in the range of 30–240 °C, accompanied by a rapid increase in photocurrent values and the phenomenon disappeared as the temperature rises to 300 °C. Moreover, a quick response speed (tr1 = 1.2 s), a high photocurrent (0.11 A at 5 V), a good rectification ratio (1.81), and a photo to dark current ratio (0.15) can be demonstrated in the p-BDD/n-WO3 NRs photodetector at 300 °C, indicating its excellent thermal stability. This work provides an effective way method for realizing UV photodetectors based on the negative differential resistance effect and reclaims the potential application of p-BDD/n-WO3 in high temperature semiconductor optoelectronic devices.

MXene-Based Sc2CHO/Sc2NHO/Sc2CHO Magnetic Tunnel Junctions for Multi-Value Logic Computing Devices: A First Principles Study

The rapid development of technologies such as machine learning and artificial intelligence has further accelerated the growth of multi-value logic (MVL) computing nanodevices. However, current MVL nanodevices based on conventional materials face the challenges of low peak–valley ratio (PVR) and unstable spin filtering effects. Therefore, the intrinsic half-metal nanoscale MXene has become the answer to the development bottleneck of MVL nanodevices for its outstanding properties such as high Curie temperature and an appropriate band structure. The present work attempts to design spintronic magnetic tunnel junctions (MTJs) based on new predicted Sc2CHO as half-metallic electrodes and Sc2NHO as semiconductor-based scattering regions. Furthermore, we simulate its transport properties from density functional theory combined with nonequilibrium Green’s function. And we have considered the effect of the length of the scattering region on MTJ performance. According to our calculations, the spintronic transport of the MTJs demonstrates up to perfect 100% polarizability spin currents stably due to the single-channel conduction capability of half-metal Sc2CHO. The MTJs exhibit a significant negative differential resistance (NDR) phenomenon, with the PVR of the type 2N reaching 1.28 × 106, the highest value among the two-dimensional spintronic nanodevices currently being theoretically explored. MTJs with a high PVR will be beneficial for the application and development of MVL nanodevices. The spin filtering effect and NDR phenomenon can be well-maintained as the scattering region length increases, and the PVR usually almost always remains 104. This is well reflected in the transmission spectra and molecular projection self-consistent Hamiltonian. The tunneling magnetoresistance phenomenon is also observed.

DFT investigation of hydrogenated cove-edged boron nitride nanoribbons for resonant tunneling diodes application

The cove-defect is found to improve the stability of the nanoribbons through bond length reconstructions at the cove-edge. Density functional theory (DFT) and non-equilibrium Green’s function (NEGF)-based first principles calculations are used to examine the structural, electronic, and quantum transport aspects of the hydrogenated cove-edge defective zigzag boron nitride nanoribbons (ZBNNRs). The additional electronic states, originated by dangling bonds at the cove-edges, exist across the Fermi level making these structures purely metallic. Additionally, with high peak-to-valley current ratios (PVCR), the quantum transport properties’ negative differential resistance (NDR) features are obtained. The highest PVCR is calculated to be 3.60 × 1016. The presented cove-edge defects can have a lot of potential for ultra-scaled devices including resonant tunnel diodes (RTDs), memory, and nanoswitches, according to the NDR phenomenon discovered in cove-edge ZBNNRs.

Influences of point defects on electron transport of two-dimensional gep semiconductor device

The quantum transport properties of defective two-dimensional (2D) GeP semiconductor nanodevice consisting of typical point defects, such as antisite defect, substitutional defect, and Schottky defect, have been studied by using density functional theory combined with non-equilibrium Green’s function calculation. The antisite defect has indistinctive influences on electron transport. However, both substitutional and Schottky defect have introduced promising defect state at the Fermi level, indicating the possibility of improvement on the carrier transport. Our quantitative quantum transport calculations of I–V b behavior have revealed that the electrical characters are enhanced. Moreover, the P atom vacancy could induce significant negative differential resistance phenomenon, and the physical mechanism is unveiled by detailed analysis. The transfer characteristic properties could be prominently improved by substitutional defect and vacancy defect. Most importantly, we have proposed a computational design of GeP-based electronic device with improved electrical performance by introducing vacancy defect. Our findings could be helpful to the practical application of novel 2D GeP semiconductor nanodevice in future.

Phononic thermal rectifier: a new proposition

We put forward a new proposition for achieving a phonon-based thermal rectifier at the nanoscale level, considering a one-dimensional phononic system. The central mechanism relies on the temperature-dependent spring constant along with the presence of mass modulation which essentially breaks the symmetry in the system and thus leads to different thermal currents in two bias polarities. Along with thermal rectification, the phenomenon of negative differential thermal resistance (NDTR) is also observed. The NDTR effect is utilized further to have the NOT gate operation. The present analysis may open up new possibilities for designing efficient thermal rectifiers and logic gates.

Flat-band states induced negative differential resistance in organic-ferromagnetic devices

Spin-dependent transport via flat-band states in organic-ferromagnetic devices with spin radicals is investigated theoretically. A spin-resolved negative differential resistance phenomenon is observed together with a spin-filtering effect. A new mechanism as bias-induced distinct localization of the spin-split flat-band states is proposed, which originates from the weaker hybridization of the flat-band states rather than the π-conjugated orbitals. The peak-to-valley ratio increases with the interaction strength between the main chain and radicals. This work explores the unique transport property of flat-band states and their intriguing prospect in designing high-performed organic spintronic devices.

Negative Differential Resistance and Long-Lived Changes in the Electrical Conductivity of Carbon Composites Induced by Electrothermal Effects

In this study, the negative differential resistance (NDR) phenomenon in two-terminal devices composed of pyrogallol-formaldehyde/ZrO2 composite materials is investigated. It is demonstrated that the NDR is caused by electrothermal effects, which can be observed through the dependence of the NDR on both voltage and temperature. Additionally, it is showed that the NDR peak current and peak/valley voltages can be effectively modulated using electrical pulses that produce mild Joule heating. This modulation arises from the formation of a conductive metastable state, which decays to equilibrium according to power law kinetics. It is suggested that this metastable state is generated through a reversible structural rearrangement induced by heat. The ability to electronically tune the NDR characteristics of carbon composites may have potential applications in electronically controlled oscillators and neuromorphic circuits.

Effect of vacancy defects on transport in all-phosphorene nanoribbon devices from first principles.

Defects in experimentally manufactured phosphorene nanoribbons (PNRs) occur unavoidably, affecting the functionality of PNR-based devices. In this work, we theoretically propose and investigate an all-PNR devices with single-vacancy (SV) defects and double-vacancy (DV) defects along the zigzag direction, accounting for both hydrogen passivation and non-passivation scenarios. We discovered that, in the case of hydrogen passivation, the DV defect can introduce in-gap states, whereas the SV defect can result in p-type doping. The unpassivated hydrogen nanoribbon exhibits an edge state with a considerable influence on the transport properties, which also masks the effect of defects on transport; furthermore, it demonstrates the phenomenon of negative differential resistance, whose occurrence and characteristics depend less on the presence or absence of defects.

Magnetic and spin transport properties of a two-dimensional magnetic semiconductor kagome lattice Nb<sub>3</sub>Cl<sub>8</sub> monolayer

Two-dimensional semiconductor materials with intrinsic magnetism have great application prospects in realizing spintronic devices with low power consumption, small size and high efficiency. Some two-dimensional materials with special lattice structures, such as kagome lattice crystals, are favored by researchers because of their novel properties in magnetism and electronic properties. Recently, a new two-dimensional magnetic semiconductor material Nb<sub>3</sub>Cl<sub>8</sub> monolayer with kagome lattice structure was successfully prepared, which provides a new platform for exploring two-dimensional magnetic semiconductor devices with kagome structure. In this work, we study the electronic structure and magnetic anisotropy of Nb<sub>3</sub>Cl<sub>8</sub> monolayer. We also further construct its <i>p-n</i> junction diode and study its spin transport properties by using density functional theory combined with non-equilibrium Green's function method. The results show that the phonon spectrum of the Nb<sub>3</sub>Cl<sub>8</sub> monolayer has no negative frequency, confirming its dynamic stability. The band gap of the spin-down state (1.157 eV) is significantly larger than that of the spin-up state (0.639 eV). The magnetic moment of the Nb<sub>3</sub>Cl<sub>8</sub> monolayer is 0.997 μ<sub>B</sub>, and its easy magnetization axis is in the plane and along the <i>x</i> axis direction based on its energy of magnetic anisotropy. Nb atoms make the main contribution to the magnetic anisotropy. When the strain is applied, the band gap of the spin-down states will decrease, while the band gap of the spin-up state is monotonously decreased from the negative (compress) to positive (tensile) strain. As the strain variable goes from -6% to 6%, the contribution of Nb atoms to the total magnetic moment gradually increases. Moreover, strain causes the easy magnetization axis of the Nb<sub>3</sub>Cl<sub>8</sub> monolayer to flip vertically from in-plane to out-plane. The designed <i>p-n</i> junction diode nanodevice based on Nb<sub>3</sub>Cl<sub>8</sub> monolayer exhibits an obvious rectification effect. In addition, the current in the spin-up state is larger than that in the spin-down state, exhibiting a spin-polarized transport behavior. Moreover, a negative differential resistance (NDR) phenomenon is also observed, which could be used in the NDR devices. These results demonstrate that the Nb<sub>3</sub>Cl<sub>8</sub> monolayer material has great potential application in the next generation of high-performance spintronic devices, and further experimental verification and exploration of this material and related two-dimensional materials are needed.

Resistive Switching Characteristics of HfO x -Based Memristor by Inserting GeTe Layer

In this study, by inserting a GeTe layer as the current suppression layer and the heating layer, we improved the forming yield (~91%), memory window (> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{{3}}$ </tex-math></inline-formula> ), and resistive switching uniformity of HfOx-based memristor. Two forming polarities including positive forming (PF) bias and negative forming (NF) bias were applied to study resistive switching characteristics. After the PF process, the device shows unstable and volatile behavior that is related to ovonic threshold switching (OTS) characteristic. Negative differential resistance (NDR) phenomenon was observed during the NF process. In addition, the device exhibits nonvolatile characteristic, multilevel resistive switching, and good endurance (> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{{5}}$ </tex-math></inline-formula> ) after the NF process. We also proposed a corresponding physical model to explain two resistive switching characteristics of the NF and PF processes.

Magnetic and spin transport properties of a two-dimensional magnetic semiconductor kagome lattice Nb&lt;sub&gt;3&lt;/sub&gt;Cl&lt;sub&gt;8&lt;/sub&gt; monolayer

Two-dimensional semiconductor materials with intrinsic magnetism have great application prospects in realizing spintronic devices with low power consumption, small size and high efficiency. Some two-dimensional materials with special lattice structures, such as kagome lattice crystals, are favored by researchers because of their novel properties in magnetism and electronic properties. Recently, a new two-dimensional magnetic semiconductor material Nb&lt;sub&gt;3&lt;/sub&gt;Cl&lt;sub&gt;8&lt;/sub&gt; monolayer with kagome lattice structure was successfully prepared, which provides a new platform for exploring two-dimensional magnetic semiconductor devices with kagome structure. In this work, we study the electronic structure and magnetic anisotropy of Nb&lt;sub&gt;3&lt;/sub&gt;Cl&lt;sub&gt;8&lt;/sub&gt; monolayer. We also further construct its &lt;em&gt;p-n&lt;/em&gt; junction diode and study its spin transport properties by using density functional theory combined with non-equilibrium Green's function method. The results show that the phonon spectrum of the Nb&lt;sub&gt;3&lt;/sub&gt;Cl&lt;sub&gt;8&lt;/sub&gt; monolayer has no negative frequency, confirming its dynamic stability. The band gap of the spin-down state (1.157 eV) is significantly larger than that of the spin-up state (0.639 eV). The magnetic moment of the Nb&lt;sub&gt;3&lt;/sub&gt;Cl&lt;sub&gt;8&lt;/sub&gt; monolayer is 0.997 μ&lt;sub&gt;B&lt;/sub&gt;, and its easy magnetization axis is in the plane and along the &lt;em&gt;x&lt;/em&gt; axis direction based on its energy of magnetic anisotropy. Nb atoms make the main contribution to the magnetic anisotropy. When the strain is applied, the band gap of the spin-down states will decrease, while the band gap of the spin-up state is monotonously decreased from the negative (compress) to positive (tensile) strain. As the strain variable goes from -6% to 6%, the contribution of Nb atoms to the total magnetic moment gradually increases. Moreover, strain causes the easy magnetization axis of the Nb&lt;sub&gt;3&lt;/sub&gt;Cl&lt;sub&gt;8&lt;/sub&gt; monolayer to flip vertically from in-plane to out-plane. The designed &lt;em&gt;p-n&lt;/em&gt; junction diode nanodevice based on Nb&lt;sub&gt;3&lt;/sub&gt;Cl&lt;sub&gt;8&lt;/sub&gt; monolayer exhibits an obvious rectification effect. In addition, the current in the spin-up state is larger than that in the spin-down state, exhibiting a spin-polarized transport behavior. Moreover, a negative differential resistance (NDR) phenomenon is also observed, which could be used in the NDR devices. These results demonstrate that the Nb&lt;sub&gt;3&lt;/sub&gt;Cl&lt;sub&gt;8&lt;/sub&gt; monolayer material has great potential application in the next generation of high-performance spintronic devices, and further experimental verification and exploration of this material and related two-dimensional materials are needed.

Ferromagnetic half-metal with high Curie temperature in Cr P nanoribbons: good material for spintronic applications.

In this work, the stability, and electronic, magnetic, and transport characteristics of chromium phosphorus nanoribbons (CrPNRs) have been investigated. The results, obtained from the non-equilibrium Green's function and density functional theory, indicate that the nanoribbon is stable in terms of binding energies as well as dynamically. The calculated electronic structure shows that this nanoribbon has an indirect band gap of about 1.67 eV for the spin-down channel and is metallic for the spin-up channel. The metallicity of the spin-up channel originates from the P-3p orbitals and the magnetic properties are due to the Cr-3d orbitals. The obtained transport properties indicate the value of the current for the spin-up state is about 50 μA. The negative differential resistance (NDR) phenomenon and also a 100% spin filtering effect are seen between voltages of 0.4 and 0.5 V. The results showed that CrPNRs have a high Curie temperature of more than 690 K, indicating that this nanoribbon is a useful ferromagnetic material for nanoelectronic devices and spintronic applications at ambient temperature.

Interlayer coupling-induced controllable negative differential thermal resistance in graphene/h-BN van der Waals heterostructure

The van der Waals (vdW) heterostructures employing graphene and hexagonal boron nitride (h-BN) have emerged as a typical system for building emergent two-dimensional devices, such as atomically thin transistors or capacitors. Herein, we study the nonlinear thermal transport in such vdW heterostructure by non-equilibrium molecular dynamics simulations. The results show that an obvious negative differential thermal resistance (NDTR) phenomenon can be observed under small temperature bias when the interlayer coupling becomes stronger. The vibrational spectra analysis manifests that the phonon filtering mechanism induced by interlayer coupling greatly hinders the interfacial thermal transport. To obtain the optimum conditions, the dependence of NDTR on the system length, lateral width, external temperature, and defect density is taken into account. Our findings extend the phonon filtering mechanism to thermal information processing.

Large negative differential resistance in triangular and square cyclopropyllithium derivative molecule

Different from hexagon-based carbon structures, the recently synthesized cyclopropyllithium derivative molecule of [{μ-c-CSiMe3C2H4}Li]4 possesses both triangular and quadrilateral rings, which is expected to exhibit interesting electronic features. Based on first-principles calculations, the electronic transport of this molecule contacted with carbon linear chain electrodes is investigated. Large negative differential resistance (NDR) phenomenon is observed. Moreover, the NDR is found to be robust to the doping on side branches which are perpendicular to the transport direction, but sensitive to the doping on main branches, which has a great influence on the NDR. NDR is found in all the doping cases, suggesting it is the intrinsic feature of such systems. Further analysis shows that, it is the suppression of the transmission peak induced by the change of energy states from delocalization to localization around the Fermi level that triggers the NDR. Our findings may throw light on the development of future molecular devices.

Modulating spintronic properties of Nitrogen passivated borophene nanoribbons

We investigate the stability, magnetic, and transport features of pristine zigzag borophene nanoribbons (ZBNRs) and those edge-passivated by H and N atoms. The calculations were performed using non-equilibrium Green’s function and density functional theory approach. Our main focus is to study the transport properties of N-passivated ZBNRs. The results show that the stability of the nanoribbon increases by passivating the edges. The magnetic features of borophene nanoribbon are affected by the hanging bond of the edges. Hydrogenation can remove the magnetism on the edge, but the passivation by N atoms can increase the magnetic properties. It is revealed that the Nitrogenation causes the negative differential resistance (NDR) phenomenon and 65% spin filtering effect. The estimated Curie temperature for N atom passivated on both edges of ZBNR (NN-ZBNR) is higher than 6000 K, indicating that NN-ZBNR may be good room-temperature ferromagnetic material for spintronic applications in the future.