Effects of the Stacking Faults on the Electrical Resistance of Highly Ordered Graphite Bulk Samples

High anisotropy and the existence of two-dimensional highly conducting interfaces at stacking faults parallel to the graphene planes of the graphite structure influence, in a non-simple way, the transport properties of highly oriented graphite. We report two related effects on the electrical resistance of highly oriented pyrolytic as well as of natural graphite bulk samples, measured with the four points method in the temperature range 300 K ≤T≤ 410 K. A qualitative and quantitative change in the temperature dependence of the resistance was obtained by simply enlarging the electrodes and contacting the edges of the internal interfaces on the same sample. Additionally, at temperatures T≳350 K the resistance can change with time. We show that this temperature-dependent annealing effect is related to the stacking faults and can irreversibly change the absolute value of the resistance and its temperature dependence. A partial recovery is obtained after leaving the sample at normal conditions for several days. The overall results stress the importance of the electrodes location on a bulk graphite sample, the contribution of the stacking faults in the interpretation of the measured transport properties and the need of systematic studies on the influence of high temperature annealing on the interfaces properties.

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Composition dependent doping and transport properties of CuGaSe2

MRS Proceedings ◽

10.1557/proc-668-h4.4 ◽

2001 ◽

Vol 668 ◽

Cited By ~ 14

Author(s):

Susanne Siebentritt ◽

Andreas Gerhard ◽

Stephan Brehme ◽

Martha Ch. Lux-Steiner

Keyword(s):

Temperature Dependence ◽

Hall Effect ◽

Transport Properties ◽

Conductivity Measurements ◽

Temperature Dependent ◽

High Quality ◽

Defect Band ◽

Doping Behavior ◽

Quality Material ◽

High Degree

ABSTRACTChalcopyrites are doped by intrinsic defects, therefore their doping behavior depends on their composition. The doping and transport properties of epitaxial CuGaSe2 layers prepared under varying Cu excess have been investigated by temperature dependent Hall effect and conductivity measurements. Two acceptors, 134 meV and 80 meV deep, and a high degree of compensation, increasing with decreasing Cu excess, are found. The temperature dependence of the mobility indicates scattering with phonons, demonstrating high quality material. Defect scattering dominates at lower temperatures for CuGaSe2 grown under moderate Cu excess. CuGaSe2 grown under little or no Cu excess shows transport in a defect band at lower temperatures.

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Pressure Effect of Seebeck Coeffcient for Zinc Doped Tin Clathrates

MRS Proceedings ◽

10.1557/proc-691-g4.4 ◽

2001 ◽

Vol 691 ◽

Author(s):

F. Chen ◽

K. L. Stokes ◽

G. S. Nolas

Keyword(s):

Electrical Conductivity ◽

High Pressure ◽

Temperature Dependence ◽

Transport Properties ◽

Power Factor ◽

Electrical Resistance ◽

Room Temperature ◽

Pressure Effect

ABSTRACTWe measured the temperature dependence of electrical resistance (R) and thermopower (S) of Cs8Zn4Sn42 under high pressure up to 1.2 GPa. Both R and ∣S∣ at room temperature increased with pressure. We observed gap widening, irreversible ∣S∣ increasing under high pressure, which were similar to the behaviors of Cs8Sn44. However, the relaxation e.ect of R for Cs8Zn4Sn42 was negligible in contrast with that of Cs8Sn44. We found that the power factor S2σ (σ: electrical conductivity) near room temperature decreased linearly with pressure. The results suggest that the defects in different forms played an important role in transport properties for tin clathrates under high pressure.

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Emergence of size induced metallic state in the ferromagnetic insulating Pr0.8Sr0.2MnO3 manganite: Breaking of surface polarons

JOURNAL OF ADVANCES IN PHYSICS ◽

10.24297/jap.v8i2.1517 ◽

2015 ◽

Vol 8 (2) ◽

pp. 2084-2093 ◽

Cited By ~ 2

Author(s):

PROLOY TARAN DAS ◽

Arun Kumar Nigam ◽

Tapan Kumar Nath

Keyword(s):

Transport Properties ◽

Metallic State ◽

Temperature Dependent ◽

Metal Insulator Transition ◽

Metal Insulator ◽

System A ◽

Surface Disorder ◽

Bulk System ◽

Magnetic Transport ◽

Grain Surface

Nano-dimensional effects on electronic-, magneto-transport properties of granular ferromagnetic insulating (FMI) Pr0.8Sr0.2MnO3 (PSMO) manganite (down to 40 nm) have been investigated in details. From the electronic and magnetic transport properties, a metallic state has been observed in grain size modulation by suppressing the ferromagnetic insulating state of PSMO bulk system. A distinct metal-insulator transition (MIT) temperature around 150 K has been observed in all nanometric samples. The observed insulator to metallic transition with size reduction can be explained with surface polaron breaking model, originates due to enhanced grain surface disorder. This proposed phenomenological polaronic model plays a significant role to understand the polaronic destabilization process on the grain surface regime of these phase separated nano-mangnatie systems. Temperature dependent resistivity and magnetoresistance data in presence of external magnetic fields are investigated in details with various compatible models.

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19F Nuclear Quadrupole Coupling in some Halomethanes

Zeitschrift für Naturforschung A ◽

10.1515/zna-1986-1-226 ◽

1986 ◽

Vol 41 (1-2) ◽

pp. 171-174 ◽

Cited By ~ 1

Author(s):

M. Frank ◽

F. Gubitz ◽

W. Ittner ◽

W. Kreische ◽

A. Labahn ◽

...

Keyword(s):

Angular Distribution ◽

Simple Model ◽

Temperature Dependence ◽

Coupling Constants ◽

Temperature Dependent ◽

Distribution Method ◽

Quadrupole Coupling ◽

Time Differential ◽

Nuclear Quadrupole

The 19F quadrupole coupling constants in CF4, CHF3, CClF3 and CHClF2 are reported. The measurements were carried out temperature dependent using the time differential perturbed angular distribution method (TDPAD). The temperature dependence can be satisfactorily described in the framework of the Bayer-Kushida theory. A simple model is used to explain the appearance of H-F and Cl-F coupling constants in CHF3/CHClF2 and CClF3, respectively.

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Temperature dependence of electrical transport properties of thin polycrystalline tellurium films on glass

Vacuum ◽

10.1016/0042-207x(75)91208-7 ◽

1975 ◽

Vol 25 (1) ◽

pp. 41

Keyword(s):

Temperature Dependence ◽

Transport Properties ◽

Electrical Transport ◽

Electrical Transport Properties ◽

Thin Polycrystalline

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Correlation holes and slow dynamics induced by fractional statistics in gapped quantum spin liquids

Nature Communications ◽

10.1038/s41467-021-21495-8 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Oliver Hart ◽

Yuan Wan ◽

Claudio Castelnovo

Keyword(s):

Transport Properties ◽

Realistic Model ◽

Feedback Mechanism ◽

Quantum Spin ◽

Spin Liquid ◽

Spin Liquids ◽

Slow Dynamics ◽

Temperature Dependent ◽

Quantum Spin Liquids ◽

Quantum Spin Liquid

AbstractRealistic model Hamiltonians for quantum spin liquids frequently exhibit a large separation of energy scales between their elementary excitations. At intermediate, experimentally relevant temperatures, some excitations are sparse and hop coherently, whereas others are thermally incoherent and dense. Here, we study the interplay of two such species of quasiparticle, dubbed spinons and visons, which are subject to nontrivial mutual statistics – one of the hallmarks of quantum spin liquid behaviour. Our results for $${{\mathbb{Z}}}_{2}$$ Z 2 quantum spin liquids show an intriguing feedback mechanism, akin to the Nagaoka effect, whereby spinons become localised on temperature-dependent patches of expelled visons. This phenomenon has important consequences for the thermodynamic and transport properties of the system, as well as for its response to quenches in temperature. We argue that these effects can be measured in experiments and may provide viable avenues for obtaining signatures of quantum spin liquid behaviour.

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Electronic Properties of Bismuth Nanowires

MRS Proceedings ◽

10.1557/proc-679-b2.4 ◽

2001 ◽

Vol 679 ◽

Cited By ~ 1

Author(s):

Stephen B. Cronin ◽

Yu-Ming Lin ◽

Oded Rabin ◽

Marcie R. Black ◽

Gene Dresselhaus ◽

...

Keyword(s):

Theoretical Model ◽

Band Structure ◽

Temperature Dependence ◽

Focused Ion Beam ◽

Ion Beam ◽

Temperature Dependent ◽

Si Substrates ◽

Bismuth Nanowires ◽

Bi Nanowire ◽

Anodic Alumina Templates

ABSTRACTThe pressure filling of anodic alumina templates with molten bismuth has been used to synthesize single crystalline bismuth nanowires with diameters ranging from 7 to 200nm and lengths of 50μm. The nanowires are separated by dissolving the template, and electrodes are affixed to single Bi nanowires on Si substrates. A focused ion beam (FIB) technique is used first to sputter off the oxide from the nanowires with a Ga ion beam and then to deposit Pt without breaking vacuum. The resistivity of a 200nm diameter Bi nanowire is found to be only slightly greater than the bulk value, while preliminary measurements indicate that the resistivity of a 100nm diameter nanowire is significantly larger than bulk. The temperature dependence of the resistivity of a 100nm nanowire is modeled by considering the temperature dependent band parameters and the quantized band structure of the nanowires. This theoretical model is consistent with the experimental results.

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