Thermopower of a multiprobe ballistic conductor

Pogosov, A. G.; Budantsev, M. V.; Uzur, D; Nogaret, Alain; Plotnikov, A. E.; Bakarov, A. K.; Toropov, A. I.

doi:10.1103/physrevb.66.201303

Cited by 15 publications

(15 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This method is not a highly efficient way to heat the lattice and the magnitude of the heating current was 1000 times larger than typical current values used in diffusion thermopower experiments [2][3][4]. We are nevertheless certain that we did measure the phonon drag and not the diffusion thermopower for the three following reasons.…”

Section: Methodsmentioning

confidence: 99%

“…The resistance [1] and the diffusion thermopower [2][3][4][5][6] of mesoscopic systems has been investigated intensively, yet no experiment to date has revealed the benefits of using the phonon-drag thermopower (PDTP) to study confined electron and phonon systems. This lack of interest can be partly traced to earlier studies of bulk semiconductors [7] and twodimensional electron gases (2DEGs) [8] that showed the phonon drag to depend only on the electron-phonon coupling and phonon parameters, not the electrical conductivity (or its derivative) as in the resistance (or the diffusion thermopower, respectively).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Phonon-drag thermopower of lateral superlattices: the role of anisotropic scattering

Uzur

Nogaret

Pogosov

et al. 2003

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

We have measured the phonon-drag thermopower of a periodically modulated two-dimensional electron gas, and report on a complex series of oscillations developing in the presence of a perpendicular magnetic field. At low electron density these oscillations are in phase with the commensurability resistance oscillations, however they become increasingly antisymmetrical with respect to B at higher electron density. We are able to explain this magnetic field dependence by proposing that the periodic potential lowers the symmetry of electron-phonon interaction. We calculate the thermopower by solving the Boltzmann equation given an electron-phonon scattering term with two-fold symmetry. Our fit of the experimental curves shows that the Brillouin zone folding enhances the electron-phonon scattering rate by a factor of two along the periodic potential and that a small misalignment (6 • ) of the heat gradient with the direction of the periodic potential is sufficient to explain the antisymmetrical oscillations. Our experiment demonstrates phonon drag as a very sensitive tool to probe the electronic and vibronic anisotropy in mesoscopic systems.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Phonon-drag thermopower of lateral superlattices: the role of anisotropic scattering

Uzur

Nogaret

Pogosov

et al. 2003

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

show abstract

“…Например, в магнетосопротивлении решeток антиточек проявляют-ся так называемые соизмеримые осцилляции, которые обусловлены совпадением в определeнных магнитных полях размеров решeтки и циклотронного диаметра орбиты электронов -возникновением геометрических резонансов [6]. Кроме того, обнаружен аномальный рост нелокального сопротивления [7] в магнитных полях, при которых выполняются условия соизмеримости, изучены магнетополевые осцилляции диффузионной термоэдс, имеющие ту же природу, что и осцилляции магне-тосопротивления [8]. Исследованы также нелинейные эффекты при пропускании большого постоянного тока и показано, что влияние постоянного электрического поля не сводится только к эффектам разогрева, а приводит также к разрушению устойчивых электронных траек-торий за счeт дрейфа в скрещенных электрическом и магнитном полях [9].…”

Section: Introductionunclassified

Баллистический магнетотранспорт в подвешенном двумерном электронном газе с периодической решeткой антиточек

Жданов¹,

Погосов²,

Буданцев³

et al. 2017

Физика И Техника Полупроводников

View full text Add to dashboard Cite

Исследовано магнетосопротивление подвешенных полупроводниковых наноструктур с двумерным элек-тронным газом, структурированным периодическими квадратными решeтками антиточек. Показано, что баллистический режим электронного транспорта сохраняется после отрыва образцов от подложки. Проведeн прямой сравнительный анализ соизмеримых осцилляций магнетосопротивления, а также их температурных зависимостей в образцах до и после подвешивания. Обнаружено, что температурные зависимости прак-тически идентичны для неподвешенных и подвешенных образцов, в то время как в нелинейном режиме, обусловленном пропусканием постоянного тока, наблюдаются существенные отличия. Соизмеримые осцил-ляции в подвешенных образцах оказываются более устойчивыми по отношению к воздействию постоянного тока, что предположительно может быть объяснено усилением электрон-электронного взаимодействия после отрыва наноструктур от высокодиэлектрической подложки.

show abstract

“…The qualitative behavior of TP in our device agrees well with that expected from ref. 17 (not shown). As expected, the strength of the feature diminishes when V tg changes from −35 V to −21 V. Figure 3(b) clearly shows a shift in its position when V tg is held constant and V pg is changed from 0 V to −0.34 V. In addition to the (1/B)-periodic SdH oscillations, we observe highly reproducible oscillations in TP at low B (< 0.3 T), which are periodic in B [boxed region in Figure 3(a)].…”

mentioning

confidence: 99%

Thermoelectric properties of electrostatically tunable antidot lattices

Goswami

Siegert

Shamim

et al. 2010

Applied Physics Letters

View full text Add to dashboard Cite

We report on the fabrication and characterization of a device which allows the formation of an antidot lattice (ADL) using only electrostatic gating. The antidot potential and Fermi energy of the system can be tuned independently. Well defined commensurability features in magnetoresistance as well as magnetothermopower are obsereved. We show that the thermopower can be used to efficiently map out the potential landscape of the ADL.A two dimensional electron system (2DES) with a regular array of scatterers is referred to as an antidot lattice (ADL). Over the past two decades, such systems have been studied in great detail revealing a variety of intriguing physical phenomena, ranging from classical pinned orbits in magnetic fields (commensurability) [1] to Ahoronov-Bohm type quantum interference effects [2]. Recently, there has been a renewed interest in ADLs, as it has been shown that they can alter the band structure of a system, resulting in modified optical [3] and electrical [4] properties. ADLs are usually fabricated by the physical removal of material (etching) in the desired region, resulting in a fixed potential profile in the underlying 2DES [1]. Less destructive techniques such as local oxidation [5] or electrostatic gating [6] have also been employed in the fabrication of ADLs. However, none of the existing techniques allow for an independent variation of the antidot potential (U AD ) and the Fermi energy (E F ) of the electron sea between the antidots. The fabrication of such devices with independent tunability of U AD and E F , would allow for a systematic study of the interplay between these two relevant energy scales. In view of recent proposals for scalable spin-based quantum information processing devices in ADLs [7,8], this tunability is highly desirable. Furthermore, recent studies in 2D mesoscopic devices in GaAs/AlGaAs heterostructures have revealed the possibility of the existence of spin correlated systems formed due to the existence of intrinsic potential modulations within the 2DES [9]. Such tunable devices provide the possibility of realizing well-ordered artificial spin-lattices with tunable magnetism in a semiconductor environment. In this Letter, we describe the properties of ADLs which are induced solely by electrostatic gating. We perform magnetoresistance (MR) and magnetothermopower (MTP) studies to show that U AD and E F can be controlled independently. We also show that thermopower (TP) is an extremely sensitive tool to study the potential landscape of the ADL system. Silicon δ-doped GaAs/AlGaAs heterostructures with a 30 nm spacer layer with an as-grown number density of 4×10 15 m −2 , and low temperature mobility of 230 m 2 /Vs (corresponding to an elastic mean free path ∼ 20 µm ) were used in our experiments.Figure 1(a) shows a schematic of the device structure. Following the definition of a mesa by wet etching, standard electron beam lithography and lift-off techniques were used to obtain a metallic (Ti/Au) perforated gate (PG). The antidot diameter (d) and spacing (a) are fi...

show abstract

Thermopower of a multiprobe ballistic conductor

Cited by 15 publications

References 10 publications

Phonon-drag thermopower of lateral superlattices: the role of anisotropic scattering

Phonon-drag thermopower of lateral superlattices: the role of anisotropic scattering

Баллистический магнетотранспорт в подвешенном двумерном электронном газе с периодической решeткой антиточек

Thermoelectric properties of electrostatically tunable antidot lattices

Contact Info

Product

Resources

About