Effective Mass Research Articles

Effective Mass and Field-Reinforced Superconductivity in Uranium Compounds

Effective Mass and Field-Reinforced Superconductivity in Uranium Compounds

Ab initio property characterisation of thousands of previously unexplored 2D materials

We perform extensive density functional theory calculations to determine the stability and elementary properties of 4249 previously unexplored monolayer crystals. The monolayers comprise the most stable subset (energy within 0.1 eV/atom of the convex hull) of a larger portfolio of two-dimensional (2D) materials recently discovered using a deep generative model and systematic lattice decoration schemes. The relaxed 2D structures are run through the basic property workflow of the Computational 2D Materials Database (C2DB) to evaluate the dynamical stability and obtain the stiffness tensor, piezoelectric tensor, deformation potentials, Born and Bader charges, electronic band structure, effective masses, plasma frequency, Fermi surface, projected density of states, magnetic moments, magnetic exchange couplings, magnetic anisotropy, topological indices, optical- and infrared polarisability. We provide statistical overviews of the property data and highlight a few specific examples of interesting materials. Our work exposes previously unknown parts of the 2D chemical space and provides a basis for the discovery of 2D materials with specific properties. All data is available in the C2DB.

Cladding-free Fermi arc surface states and topological directional couplers in ideal photonic Weyl metamaterials

Photons can freely propagate in a vacuum, making it not a simple insulator but rather a conductor for photons. Consequently, in topological photonics, domain wall structures with opposing effective mass terms are used as cladding to confine electromagnetic waves. This approach is necessary to demonstrate topological edge/surface waves and Fermi arc surface states (FASS). Here, we show that the cladding-free FASS with high field localization at the boundary can be achieved using ideal Weyl gyromagnetic metamaterials (GMs). In these GMs, the ideal Weyl semimetal phase exists due to the dispersionless longitudinal modes. At the boundary of the GMs-vacuum system, the cladding-free FASS connects the projections of Weyl nodes with opposite chirality, thanks to the bulk-boundary correspondence principle. We further confirm that chiral boundary modes can propagate without experiencing scattering or backward reflection, i.e., they can advance seamlessly approximately various types of defects. Remarkably, various types of topological directional couplers are achieved by utilizing cladding-free FASS in an ideal gyromagnetic medium. Our theoretical analysis reveals that the underlying operational principle for accomplishing these nonreflecting directional couplers is due to the single coupling channel between the cladding-free FASS and the multi-type scatterers of the continuous media. Furthermore, the controllable propagation and topological directional coupling of cladding-free FASS can be further explored by adjusting the ideal gyromagnetic medium and boundary configurations of the continuous media system. This research offers increased flexibility for the development of cladding-free and directionally coupled topological devices.

Aspects of non-topological soliton stars in a class of induced gravity theories

We explore some interesting properties of soliton stars arising in a class of effective gravity theories having a Higgs scalar field that serves a dual role of generating an effective mass of a fermion field as well as generating an effective gravitational constant. With a suitable choice of non-minimal coupling, such solitons have the canonical effective gravitational constant in their exterior while in the interior the effective gravitational constant could be arbitrarily smaller. Such a choice enables an exact determination of gravitational effects on the total conserved energy of the soliton. While the external metric of such a soliton is the standard Schwarzschild metric, the interior entropy is much larger than that of a black hole of the same equilibrium temperature.

Clinicopathological characteristics of gangliogliomas with anaplastic morphology

Objective: To investigate the clinical, radiological, and pathological features of anaplastic gangliogliomas (AGGs) and to determine whether these tumors represent a distinct entity. Methods: Consecutive 667 cases of ganglioglioma (GG) diagnosed at the Xuanwu Hospital, Capital Medical University, Beijing, China between January 2015 and July 2023 were screened. Among these cases, 9 pathologically confirmed AGG cases were identified. Their clinical, radiological, treatment, and outcome data were analyzed retrospectively. Most of the tumor samples were subject to next-generation sequencing, while a subset of them were subject to DNA methylation profiling. Results: Among the 9 patients, there were five males and four females, with a median age of 8 years. Epileptic seizures (5/9) were the most frequently presented symptom. Radiological examinations showed three types of radiological manifestations: four cases showed abnormal MRI signals with no significant mass effects and mild enhancement; two cases demonstrated a mixed solid-cystic density lesion with peritumoral edema, which showed significant heterogeneous enhancement and obvious mass effects, and one case displayed cystic cavity formation with nodules on MRI, which showed evident enhancements. All cases exhibited mutations that were predicted to activate the MAP kinase signaling pathway, including seven with BRAF p.V600E mutation and two with NF1 mutation. Five AGGs with mutations involving the MAP kinase signaling pathway also had concurrent mutations, including three with CDKN2A homozygous deletion, one with a TERT promoter mutation, one with a H3F3A mutation, and one with a PTEN mutation. Conclusions: AGG exhibits a distinct spectrum of pathology, genetic mutations and clinical behaviors, differing from GG. Given these characteristics suggest that AGG may be a distinct tumor type, further expansion of the case series is needed. Therefore, a comprehensive integration of clinical, histological, and molecular analyses is required to correctly diagnose AGG. It will also help guide treatments and prognostication.

Giant cavernous aneurysms occluded by aneurysmal thrombosis, calcification, parent artery occlusion: A case report and review of literature

BACKGROUND Patients with giant intracranial aneurysms (GIAs) are at a high risk of rupture, morbidity, and mortality even after surgical or endovascular treatment. We described a case of a spontaneously occluded GIA secondary to gradual growth of the GIA, continuously progressed aneurysmal thrombosis, complete aneurysmal calcification and complete occlusion of the parent artery-the right internal carotid artery (RICA). CASE SUMMARY A 72-year-old female patient complained of sudden pain in her right eye upon admission to our hospital. She had been diagnosed with a GIA [30 mm (axial) × 38 mm (coronal) × 28 mm (sagittal)] containing an aneurysmal thrombus located in the cavernous sinus segment of RICA diagnosed by magnetic resonance imaging (MRI), enhanced MRI, and magnetic resonance angiography more than 14 years ago. Later, with slow growth of the cavernous carotid GIA, aneurysmal thrombosis progressed continuously, spontaneous occlusion of the RICA, complete aneurysmal calcification, and occlusion of the GIA occurred gradually. She had no history of subarachnoid hemorrhage but missed the chance for endovascular therapy at an early stage. As a result, she was left with severe permanent sequelae from the injuries to the right cranial nerves II, III, IV, V1/V2, and VI. CONCLUSION The risk of rupture of the cavernous carotid GIAs was relatively low and possibly further be reduced by the stasis flow and spontaneous occlusion of the parent artery internal carotid artery (ICA) induced by the mass effect of the cavernous carotid GIAs and the extremely rare aneurysmal calcification. However, nowadays, it is advisable to recommend early endovascular treatment for the cavernous carotid GIAs to prevent injuries to the surrounding intracranial nerves and occlusion of the ICA, mainly caused by the mass effect of the cavernous carotid GIAs.

Estimation of Maximum <i>zT</i> in Cu<sub>3</sub>SbSe<sub>4</sub> for Different Starting Materials Content

Cu<sub>3</sub>SbSe<sub>4</sub> is considered a promising thermoelectric material because of its large effective mass and low thermal conductivity, originating from its unique lattice structure. However, Cu<sub>3</sub>SbSe<sub>4</sub> has intrinsically low carrier concentration and relatively high electric resistance which limit performance. Recently, a <i>zT</i> improvement in Cu<sub>3</sub>SbSe<sub>4</sub> was reported where doping/precipitation is controlled by changing the content of the starting materials. However, the effect of these changes in starting content on electronic band structures has not been studied. Here, we investigate how the change in starting materials content (<i>x</i> varying from 6 to 20) affects band parameters like density-of-states effective mass (<i>m<sub>d</sub></i> *), non-degenerate mobility (<i>μ<sub>0</sub></i>), weighted mobility (<i>μ<sub>W</sub></i>), and B-factor using the Single Parabolic Band (SPB) model. For <i>x</i> greater than 8, precipitation of the secondary phase (CuSe) was observed, and the band parameters changed differently for <i>x</i> greater than 8. The <i>m<sub>d</sub></i> * increases up to <i>x</i> = 8 and then rapidly decreases for <i>x</i> > 8. For <i>μ<sub>0</sub></i>, an overall decrease is observed for increasing <i>x</i>, but the rate of decrease is suppressed for <i>x</i> > 8. The <i>μ<sub>W</sub></i> reaches the maximum at <i>x</i> = 8. As <i>x</i> increases, the experimental lattice thermal conductivity also increases, especially for <i>x</i> > 8. Therefore, the B-factor, which is directly related to the theoretical maximum zT, becomes maximum at = 8. Hence the SPB model predicts a maximum <i>zT</i> of 0.0484 for <i>x</i> = 8 at 300 K, which is 15.5% higher than the experimental <i>zT</i> of 0.0419, which can be achieved by tuning the Hall carrier concentration to 4.44 × 10<sup>19</sup> cm<sup>-3</sup>.

The photocatalytic degradation performance of Dion-Jacobson-type layered perovskites AMCa2Ta3O10 (AM=Rb, Cs): A DFT study

The structural, electronic, redox potential, mechanical, photocatalytic, and optical properties of the Dion-Jacobson-type triple-layered perovskites AMCa2Ta3O10 (AM = Rb, Cs) are investigated via density functional theory (DFT) study. The electronic properties are calculated through HSE-06 functional technique which confirmed the semiconducting behavior with the energy band gap values of 1.67 eV and 1.71 eV for RbCa2Ta3O10 and CsCa2Ta3O10, respectively. The calculated results of redox potential indicate that both materials are favorable for water splitting and as an agent for pollutant degradation. Both studied compounds exhibit a reduced effective mass of electrons, which suggests the high capacity to transfer the charge to the surface, indicative of superior electrical conductivity. Poisson's and Pugh's ratios suggest that both the materials are brittle. Optical parameters are calculated within the energy range of 0–6 eV, which strongly correlates with the energy band gap's high absorption and low reflection in the visible region. Our findings indicate high photocatalytic efficiency in organic pollutant degradation, suggesting the potential for developing advanced photocatalytic devices for water splitting and environmental pollutant decomposition.

Dependence temperature on effective mass and susceptibility in quantum well-wires

In this study, we investigated the simulation impact of carrier density and temperature on properties such as susceptibility and effective mass of electrons in GaAs/Al x Ga1−x As quantum-well wires, involving the treatment of Coulomb interaction and the interaction between electrons and holes with longitudinal optical phonons (LO-phonon) on an equal basis. The susceptibility and effective mass were calculated and compared with the results when no phonon coupling was considered. Furthermore, the key findings were compared with results from the sum-rule version of the Singwi-Tosi-Land-Sj ö lander (STLS) theory, mean-spherical approximation (MSA) theory, and there is a high level of concordance between this formula and experimental values obtained by other researchers. Our results reveal that carrier concentration and temperature significantly affect susceptibility and effective mass of the quantum well-wires in both cases, with LO-phonon contributions. These results contribute to illuminating how Coulomb interactions and exchange-correlation energies influence the susceptibility and effective mass of GaAs/Al x Ga1−x As across a broad range of temperature and carrier density conditions.

Preparation of Nb5+ Doped Na3V2(PO4)3 Cathode Material for Sodium Ion Batteries.

Sodium-ion batteries (SIBs) have emerged as a promising alternative to lithium-ion batteries (LIBs) due to the abundance and low cost of sodium resources. Cathode material plays a crucial role in the performance of sodium ion batteries determining the capacity, cycling stability, and rate capability. Na3V2(PO4)3 (NVP) is a promising cathode material due to its stable three-dimensional NASICON structure, but its discharge capacity is low and its decay is serious with the increase of cycle period. We focused on modifying NVP cathode material by coating carbon and doping Nb5+ ions for synergistic electrochemical properties of carbon-coated NVP@C as a cathode material. X-ray diffraction analysis was performed to confirm the phase purity and crystal structure of the Nb5+ doped NVP material, which exhibited characteristic diffraction peaks that matched well with the NASICON structure. Nb5+-doped NVP@C@Nbx materials were prepared using the sol-gel method and characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Raman and Brunauer -Emmett-Teller (BET) analysis. First-principles calculations were performed based on density functional theory. VASP and PAW methods were chosen for these calculations. GGA in the PBE framework served as the exchange-correlation functional. The results showed the NVP unit cell consisted of six NVP structural motifs, each containing octahedral VO6 and tetrahedral PO4 groups to form a polyanionomer [V2(PO4)3] along with the c-axis direction by PO4 groups, which had Na1(6b) and Na2(18e) sites. And PDOS revealed that after Nb doping, the d orbitals of the Nb atoms also contributed electrons that were concentrated near the Fermi surface. Additionally, the decrease in the effective mass after Nb doping indicated that the electrons could move more freely through the material, implying an enhancement of the electron mobility. The electrochemical properties of the Nb5+ doped NVP@C@Nb cathode material were evaluated through cyclic voltammetry (CV), galvanostatic charge-discharge tests, electrochemical impedance spectroscopy (EIS), and X-ray photoelectric spectroscopy (XPS). The results showed that NVP@C@Nb0.15 achieved an initial discharge capacity as high as 114.27 mAhg-1, with a discharge capacity of 106.38 mAhg-1 maintained after 500 cycles at 0.5C, and the retention rate of the NVP@C@Nb0.15 composite reached an impressive 90.22%. NVP@C@Nb0.15 exhibited low resistance and high capacity, enabling it to create more vacancies and modulate crystal structure, ultimately enhancing the electrochemical properties of NVP. The outstanding performance can be attributed to the Nb5+-doped carbon layer, which not only improves electronic conductivity but also shortens the diffusion length of Na+ ions and electrons, as well as reduces volume changes in electrode materials. These preliminary results suggested that the as-obtained NVP@C@Nb0.15 composite was a promising novel cathode electrode material for efficient sodium energy storage.

Progressive Multifocal Leukoencephalopathy in a Patient With Cirrhosis and Hepatocellular Carcinoma

The following case describes a constellation of progressive cognitive and motor deficits in a 73-year-old man with cirrhosis and history of early-stage hepatocellular carcinoma confined to his liver. He had deficits in calculation, language, and writing, as well as subtle right-sided weakness. Magnetic resonance imaging (MRI) of the brain demonstrated non-enhancing white matter lesions without mass effect in the bilateral parietal and left occipitotemporal regions, correlating with neurologic exam findings. The patient’s basic blood and cerebrospinal fluid (CSF) studies were within normal limits. Our differential included inflammatory and demyelinating conditions, hepatic encephalopathy, posterior reversible encephalopathy syndrome, progressive multifocal leukoencephalopathy (PML), and central nervous system (CNS) tumors. He did not improve with an empiric course of high-dose steroids or adequate hepatic encephalopathy treatment. A repeat lumbar puncture sent for additional CSF studies revealed a positive John Cunningham (JC) virus PCR test, confirming diagnosis of PML. Although the patient did not have any known overt immunosuppressive condition or treatment, the patient’s cirrhosis and age placed him at higher risk for developing JC virus CNS reactivation. In a published case series of patients with PML and no classic immunosuppressive condition that includes several patients with concomitant cirrhosis, prognosis is much worse compared to those with known, reversible causes of immunosuppression.

Determination of the Collins-Soper Kernel from Lattice QCD.

This Letter presents a determination of the quark Collins-Soper kernel, which relates transverse-momentum-dependent parton distributions (TMDs) at different rapidity scales, using lattice quantum chromodynamics (QCD). This is the first such determination with systematic control of quark mass, operator mixing, and discretization effects. Next-to-next-to-leading logarithmic matching is used to match lattice-calculable distributions to the corresponding TMDs. The continuum-extrapolated lattice QCD results are consistent with several recent phenomenological parametrizations of the Collins-Soper kernel and are precise enough to disfavor other parametrizations.

Bi(III)‐based oxide semiconductors with ambipolar doping: (Na, K)BiO2

AbstractBi(III)‐based oxides are emerging as important semiconductors for future electronic applications. Through hybrid density functional theory calculations and defect analysis, we demonstrate that ABi(III)O2 (A = Na or K) is a promising wide‐band‐gap bipolar semiconductor. Our calculations predict ABiO2 to have a large band gap of 1.97 eV for NaBiO2 and 2.77 eV for KBiO2. Unlike widely‐used oxide semiconductors such as In2O3 and ZnO, the spatially extended cation states (Bi 6s) of ABiO2 significantly contribute to the valence band maximum, enhancing p‐type dopability. We indeed show that potential acceptors, such as SrBi, produce shallow levels. In addition, n‐type doping is found to be possible through the extrinsic doping of heterovalent elements such as Te and F. The band‐structure analysis reveals that ABiO2 has small effective masses for electrons and holes (< 1m0 where m0 is the electron rest mass), indicating favorable electron and hole transport properties.

Probing molecular spectral functions and unconventional pairing using Raman spectroscopy

An impurity interacting with an ultracold Fermi gas can form either a polaron state or a dressed molecular state, the molaron, in which the impurity forms a bound state with one gas particle. This molaron state features rich physics, including a negative effective mass around unitarity and a first-order transition to the polaron state. However, these features have remained so far experimentally inaccessible. In this work we show theoretically how the molaron state can be directly prepared experimentally even in its excited states using Raman spectroscopy techniques. Initializing the system in the ultrastrong coupling limit, where the binding energy of the molaron is much larger than the Fermi energy, our protocol maps out the momentum-dependent spectral function of the molecule. Using a diagrammatic approach we furthermore show that the molecular spectral function serves as a direct precursor of the elusive Fulde-Ferell-Larkin-Ovchinnikov phase, which is realized for a finite density of fermionic impurity particles. Our results pave the way to a systematic understanding of how composite particles form in quantum many-body environments and provide a basis to develop new schemes for the observation of exotic phases of quantum many-body systems. Published by the American Physical Society 2024

Computation of the near-infrared electro-absorption in GeSn/SiGeSn step quantum wells

In this study, we propose a theoretical simulation of the type-I step quantum well obtained from GeSn/SiGeSn to scan a wide range of telecommunication wavelengths and obtain near-infrared optical modulators. At T = 300 K, the band discontinuities and energy gap between stretched Ge1−xSnx and relaxed Si0.1Ge0.9−ySny due to the acquisition of the heterostructure were calculated.Then, optimization of this heterostructure based on (Si) GeSn was performed using the solid theory model to balance out the composition y of Si0.1Ge0.9-ySny relaxed and thickness of Ge0.91Sn0.09 QWs. The eigenenergies and their related wavefunctions are computed by solving the Schrödinger equation using the finite difference method under the framework of the effective mass approximation. Depending on the y concentration, the energy levels of the electron and the heavy hole, the change of transition energies and oscillator strength were examined for different well widths. Additionally, the absorption coefficient with y concentration and structure parameters were examined.From the findings obtained, it was determined that this material group is very important to obtain high efficiency from electro-absorption modulators covering the 1.55 μm wavelength range.

Proactive cursorial and ambush predation risk avoidance in four African herbivore species.

Most herbivores must balance demands to meet nutritional requirements, maintain stable thermoregulation and avoid predation. Species-specific predator and prey characteristics determine the ability of prey to avoid predation and the ability of predators to maximize hunting success. Using GPS collar data from African wild dogs, lions, impala, tsessebes, wildebeest and zebra in the Okavango Delta, Botswana, we studied proactive predation risk avoidance by herbivores. We considered predator activity level in relation to prey movement, predator and prey habitat selection, and preferential use of areas by prey. We compared herbivore behaviour to lion and wild dog activity patterns and determined the effect of seasonal resource availability and prey body mass on anti-predator behaviour. Herbivore movement patterns were more strongly correlated with lion than wild dog activity. Habitat selection by predators was not activity level dependent and, while prey and predators differed to some extent in their habitat selection, there were also overlaps, probably caused by predators seeking habitats with high prey abundance. Areas favoured by lions were used by herbivores more when lions were less active, whereas wild dog activity level was not correlated with prey use. Prey body mass was not a strong predictor of the strength of proactive predation avoidance behaviour. Herbivores showed stronger anti-predator behaviours during the rainy season when resources were abundant. Reducing movement when top predators are most active and avoiding areas with a high likelihood of predator use during the same periods appear to be common strategies to minimize predation risk. Such valuable insights into predator-prey dynamics are only possible when using similar data from multiple sympatric species of predator and prey, an approach that should become more prevalent given the ongoing integration of technological methods into ecological studies.

Multiphysics simulation study of thermal stress effects in nanoscale FinFETs heterogeneously integrated with GaN high-power device on silicon substrate

Heterogeneous integration enables high-density integration to improve system functionality, but meanwhile brings reliability concerns due to the intensification of temperature and thermal stress. However, research on thermal stress effects in nanoscale transistors within heterogeneous integrated circuit is still very limited up to now. Multiphysics computation for the heterogeneous integration of nanoscale p-FinFET with GaN high electron mobility transistor (HEMT) on silicon substrate is performed. Firstly, self-heating of GaN HEMT induced thermal stress is simulated. Then, thermal stress effects induced by the GaN HEMT on quantum transport in the FinFET at different locations are compared and analyzed, including the hole effective mass, hole average velocity, on/off-state current, and on-off ratio. Moreover, the impacts of crystal orientation configurations are further discussed. Simulation results show that the impact of thermal stress on FinFET is highly dependent on the Si crystal orientation and its location relative to GaN HEMT. Taking the FinFET with (001)/[110] confinement/transport orientation, which is at a distance of RFET and an angle of φ from the GaN HEMT as an example, thermal stress induces the significant reductions in Ion and Ioff of FinFET at φ = π/2 and φ = 3π/2, and the increases of Ion and Ioff in FinFET at φ = 0 and φ = π, but has small impact on FinFETs located diagonally to the GaN HEMT.

Orbital Solitary Fibrous Tumor in a Commercial Airline Pilot.

BACKGROUND: In the literature, central serous retinopathy (CSR) accompanying solitary fibrous tumors (SFT) in a pilot has not been reported. In airline pilots, mass effect-related symptoms such as diplopia, ptosis, etc., seen with orbital tumors may endanger flight safety.CASE REPORT: A 62-yr-old male commercial airline pilot presented with blurred vision in the right eye. He had been receiving treatment for 2 mo because of CSR. His visual acuity was 10/20 in the right eye and 20/20 in the left. During examination, ptosis and exophthalmos were noticed in the right eye. Ocular movements were free in all cardinal directions and there was downward displacement in the right eye. There was no diplopia. Magnetic resonance imaging revealed a 1.5- to 2-cm well-defined contrast-enhancing mass in the lateral extraconal orbit. His medical flight certificate was suspended for 3 mo due to decreased visual acuity and superior visual defect. Superior orbitotomy was performed without any complication. Ptosis and CSR had regressed 1 wk after surgery. All systemic and ophthalmological examinations met aviation medical certificate requirements. He returned to flight on the condition of being checked every 3 mo. At the 1-yr follow-up, there was no sign of recurrences of SFT or CSR.DISCUSSION: SFTs are slow-growing neoplasms that can manifest symptoms related to mass effect. In the current literature, there are no reported cases of the coexistence of orbital SFT and CSR or pilots able to resume flight duties only 1 wk after a successful orbitotomy and tumor resection surgery.Altinbas M, Ozpınar A, Akbaba M, Nacaroglu SA, Sargolzaeimoghaddam M, Sargolzaeimoghaddam M. Orbital solitary fibrous tumor in a commercial airline pilot. Aerosp Med Hum Perform. 2024; 95(6):333-336.

Ultrasensitive Proteomics of Trace Cardiac Tissues with Anchor-Nanoparticles.

Pathological cardiac hypertrophy is a complex process that often leads to heart failure. Label-free proteomics has emerged as an important platform to reveal protein variations and to elucidate the mechanisms of cardiac hypertrophy. Endomyocardial biopsy is a minimally invasive technique for sampling cardiac tissue, but it yields only limited amounts of an ethically permissible specimen. After regular pathological examination, the remaining trace samples pose significant challenges for effective protein extraction and mass spectrometry analysis. Herein, we developed trace cardiac tissue proteomics based on the anchor-nanoparticles (TCPA) method. We identified an average of 6666 protein groups using ∼50 μg of myocardial interventricular septum samples by TCPA. We then applied TCPA to acquire proteomics from patients' cardiac samples both diagnosed as hypertrophic hearts and myocarditis controls and identified significant alterations in pathways such as regulation of actin cytoskeleton, oxidative phosphorylation, and cGMP-PKG signaling pathway. Moreover, we found multiple lipid metabolic pathways to be dysregulated in transthyretin cardiac amyloidosis compared to other types of cardiac hypertrophy. TCPA offers a new technique for studying pathological cardiac hypertrophy and can serve as a platform toolbox for proteomic research in other cardiac diseases.

Investigation on the electrical and thermal properties of Cr-doped FeSe2 alloys

FeSe2 is a p-type semiconductor with a narrow band gap, which can be considered a potential thermoelectric material. Herin, the electrical and thermal properties of Cr-doped FeSe2, Fe1-xCrxSe2 (x = 0, 0.03, 0.06, and 0.09), polycrystalline alloys are investigated. All compositions show single-phase marcasite structures of FeSe2 with gradual decreases in lattice parameters with Cr doping x. With increasing x, the electrical conductivity gradually increases from 13 (x = 0) to 46 S/cm (x = 0.09), owing to a large increase in carrier concentration originated from the substitution of Cr2+ and Cr3+ at the Fe site. However, the magnitude of Seebeck coefficient decreases considerably at 300 K, resulting in decrease in power factor. In addition, the density-of-state effective mass decreases significantly from 6.0 m0–1.04 m0. At 700 K, the decrease in Seebeck coefficient is less severe. Although the total and lattice thermal conductivity decrease at all temperatures owing to additional phonon scattering of the extrinsic Cr ions, a thermoelectric figure of merit, zT, generally decreases compared to that of the pristine sample due to power factor decrease at 300 K. Meanwhile, a slight increase of zT to 0.11 is observed for x = 0.06 at 700 K.