Do you want to publish a course? Click here

Can 1D topological states explain the extraordinary thermoelectric properties of Bi 2 Te 3 ? An exact analytical solution in the Tomonaga-Luttinger liquids (TLLs) framework

114   0   0.0 ( 0 )
 Added by Piotr Chudzinski
 Publication date 2020
  fields Physics
and research's language is English
 Authors P.Chudzinski




Ask ChatGPT about the research

Topological insulators are frequently also one of the best known thermoelectric materials. It has been recently discovered that in 3D topological insulators each skew dislocation can host a pair of 1D topological states a helical TLL. We derive exact analytical formulas for thermoelectric Seebeck coefficient in TLL and investigate up to what extent one can ascribe the outstanding thermoelectric properties of Bi 2 Te 3 to these 1D topological states. To this end we take a model of a dense dislocation network and find an analytic formula for an overlap between 1D (the TLL) and 3D electronic states. Our study is applicable to a weakly n-doped Bi 2 Te 3 but also to a broader class of nano-structured materials with artificially created 1D systems. Furthermore, our results can be used at finite frequency settings e.g. to capture transport activated by photo-excitations.



rate research

Read More

123 - Shama , Goutam Sheet , 2020
We report the growth and magneto-transport studies of Pd$_{3}$Bi$_{2}$S$_{2}$ (PBS) thin films synthesized by pulsed laser deposition (PLD) technique. The magneto-transport study on pristine and post annealed films show the presence of more than one type of charge carrier with a carrier concentration in the range $0.6$ - $2.26~times$ 10$^{21}$ cm$^{-3}$ and mobility in the range 0.96 - 1.73 $times$ 10$^{2}$ cm$^{2}$/Vs. At low temperatures a logarithmic increase in conductivity is observed which indicates the presence of weak anti-localization (WAL). The magnetotransport data is analysed within the Hikami-Larkin-Nagaoka (HLN) theory. It is found that temperature dependence of the dephasing length cant be explained only by electron-electron scattering and that electron-phonon scattering also contributes to the phase relaxation mechanism in PBS films.
266 - P. Chudzinski 2018
The problem of photoemission from a quasi-1D material is studied. We identify two issues that play a key role in the detection of gapless Tomonaga-Luttinger liquid (TLL) phase. Firstly, we show how a disorder -- backward scattering as well as forward scattering component, is able to significantly obscure the TLL states, hence the initial state of ARPES. Secondly, we investigate the photo-electron propagation towards a samples surface. We focus on the scattering path operator contribution to the final state of ARPES. We show that, in the particular conditions set by the 1D states, one can derive exact analytic solution for this intermediate stage of ARPES. The solution shows that for particular energies of incoming photons the intensity of photo-current may be substantially reduced. Finally, we put together the two aspects (the disorder and the scattering path operator) to show the full, disruptive force of any inhomogeneities on the ARPES amplitude.
Using first-principles calculations combined with Boltzmann transport theory, we investigate the effects of topological edge states on the thermoelectric properties of Bi nanoribbons. It is found that there is a competition between the edge and bulk contributions to the Seebeck coefficients. However, the electronic transport of the system is dominated by the edge states because of its much larger electrical conductivity. As a consequence, a room temperature value exceeding 3.0 could be achieved for both p- and n-type systems when the relaxation time ratio between the edge and the bulk states is tuned to be 1000. Our theoretical study suggests that the utilization of topological edge states might be a promising approach to cross the threshold of the industrial application of thermoelectricity.
The ability to manipulate individual atoms and molecules using a scanning tunnelling microscope (STM) has been crucial for the development of a vast array of atomic scale devices and structures ranging from nanoscale motors and switches to quantum corrals. Molecular motors in particular have attracted considerable attention in view of their potential for assembly into complex nanoscale machines. Whereas the manipulated atoms or molecules are usually on top of a substrate, motors embedded in a lattice can be very beneficial for bottom-up construction, and may additionally be used to probe the in uence of the lattice on the electronic properties of the host material. Here, we present the discovery of controlled manipulation of a rotor in Fe doped Bi$_{2}$Se$_{3}$. We find that the current into the rotor, which can be finely tuned with the voltage, drives omni-directional switching between three equivalent orientations, each of which can be frozen in at small bias voltage. Using current fluctuation measurements at 1MHz and model simulations, we estimate that switching rates of hundreds of kHz for sub-nA currents are achieved.
198 - Z. S. Lim , L. E. Chow , P. Yang 2021
Using SrRuO3-based thin film heterostructures, we aim to resolve the two debated interpretations that distinguish between the genuine Topological Hall Effect (THE) and the artefactual humps produced from overlapping double Karplus-Luttinger Anomalous Hall Effects (KL-AHE), without magnetic imaging. Firstly, we selected two heterostructures with similar Hall Effect but with contrasting octahedral rotations/tilts, providing a clue to determining the presence/absence of Dzyaloshinskii-Moriya Interaction. Secondly, we employ the {theta}-rotation of magnetic field from out-of-plane to in-plane as the critical judgemental tool. The first heterostructure showing field-position of Hall hump diverging with ~1/cos({theta}) is correctly reproduced using the double KL-AHEs. Yet, the second one showing constant hump field versus {theta} behaviour agrees with a micromagnetic simulation with Neel-Skyrmions and is thus convincingly assigned as THE. Lastly, for a general system evolving with increasing magnetic field from two-dimensional Skyrmion-lattice into collinear ferromagnetic in the real-space, we further discuss about the corresponding evolution of k-space band structure from gapped massive Dirac Fermion into Weyl Fermion, consistent to past literatures. Its associated transformation from Mirror Anomaly into Chiral Anomaly is detectable via electrical transport and further assisted in resolving the aforementioned debate. We hence emphasize the two schemes as useful, generic electrical measurement protocols for future search of magnetic Skyrmions.
comments
Fetching comments Fetching comments
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا