Thermoelectric properties of Mexican-hat band structures

Nurhuda, Muhammad; Nugraha, Ahmad R. T.; Hanna, Muhammad Y.; Suprayoga, Edi; Hasdeo, Eddwi H.

doi:10.1088/2043-6254/ab7225

Cited by 6 publications

(6 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…That would be able to reveal more details of the excited-state electron dynamics. It is worth noting that the flat band of Te could be a potential platform to explore flat-band physics in the future. − …”

mentioning

confidence: 99%

Reveal Ultrafast Electron Relaxation across Sub-bands of Tellurium by Time- and Energy-Resolved Photoemission Microscopy

Lyu,

Li,

Jiang

et al. 2023

Nano Lett.

View full text Add to dashboard Cite

Exploring ultrafast carrier dynamics is crucial for the materials' fundamental properties and device design. In this work, we employ time-and energy-resolved photoemission electron microscopy with tunable pump wavelengths from visible to near-infrared to reveal the ultrafast carrier dynamics of the elemental semiconductor tellurium. We find that two discrete sub-bands around the Γ point of the conduction band are involved in excited-state electron ultrafast relaxation and reveal that hot electrons first go through ultrafast intra sub-band cooling on a time scale of about 0.3 ps and then transfer from the higher sub-band to the lower one on a time scale of approximately 1 ps. Additionally, theoretical calculations reveal that the lower one has flat-band characteristics, possessing a large density of states and a long electron lifetime. Our work demonstrates that TR-and ER-PEEM with broad tunable pump wavelengths are powerful techniques in revealing the details of ultrafast carrier dynamics in time and energy domains.

show abstract

mentioning

confidence: 99%

Reveal Ultrafast Electron Relaxation across Sub-bands of Tellurium by Time- and Energy-Resolved Photoemission Microscopy

Lyu,

Li,

Jiang

et al. 2023

Nano Lett.

View full text Add to dashboard Cite

show abstract

“…Having the optimised systems and their associated electronic structures, we continue to calculate the thermoelectric properties based on semi-classical BTE with a CRTA as implemented in the BOLTZTRAP2 package [33]. TE coefficients are calculated by using an advantageous formula derived from BTE, called TE kernels [34], expressed by…”

Section: Computational Detailsmentioning

confidence: 99%

Thermoelectric properties of monolayer and bilayer buckled XTe (X = Ge, Sn, and Pb)

Lubis¹,

Amalia²,

Wella³

et al. 2022

Adv. Nat. Sci: Nanosci. Nanotechnol.

View full text Add to dashboard Cite

Lowering the dimension of 3D materials, so that the confinement length L of the low-dimensional material is less than the thermal wavelength Λ of its bulk phase, is expected to be a sufficient way to enhance their thermoelectric performances. Using density functional theory incorporating the linearised Boltzmann transport equation with a constant relaxation time approximation, we calculate the electronic and thermoelectric properties of monolayer and bilayer XTe (X = Ge, Sn, and Pb). It is shown that the ideal figure of merit of monolayer XTe is larger than that of bilayer XTe, suggesting the importance of downsizing the bulk XTe up to single-layer thickness to have a better thermoelectric performance. The n-type monolayer buckled SnTe is predicted to exhibit remarkable thermoelectric performance with ZT > 1.6 at T = 900 K compared to other monolayer and bilayer XTe.

show abstract

“…However, according to [3,30], such TDF cannot be achieved in the real material. Even if the DOS shows the Van Hove singularities, the TDF is not divergent because the DOS term is cancelled out with the square of longitudinal velocity term resulting in a finite ZT [31]. The narrow transport distribution gives more conducting channels that increase σ while giving a low κ el because of the (E-μ) 2 factor that κ el has [3,30].…”

Section: Thermoelectric Propertiesmentioning

confidence: 99%

Non-universal scaling of thermoelectric efficiency in 3D and 2D thermoelectric semiconductors

Octavian¹,

Hasdeo²

2021

Adv. Nat. Sci: Nanosci. Nanotechnol.

View full text Add to dashboard Cite

We performed the first-principles calculation on common thermoelectric semiconductors Bi2Te3, Bi2Se3, SiGe, and PbTe in bulk three-dimension (3D) and two-dimension (2D). We found that miniaturisation of materials does not generally increase the thermoelectric figure of merit (ZT) according to the Hicks and Dresselhaus (HD) theory. For example, ZT values of 2D PbTe (0.32) and 2D SiGe (0.04) are smaller than their 3D counterparts (0.49 and 0.09, respectively). Meanwhile, the ZT values of 2D Bi2Te3 (0.57) and 2D Bi2Se3 (0.43) are larger than the bulks (0.54 and 0.18, respectively), which agrees with HD theory. The HD theory breakdown occurs because the band gap and band flatness of the materials change upon dimensional reduction. We found that flat bands give a larger electrical conductivity (σ) and electronic thermal conductivity (κ el) in 3D materials, and smaller values in 2D materials. In all cases, maximum ZT values increase proportionally with the band gap and saturate for the band gap above 10 k B T. The 2D Bi2Te3 and Bi2Se3 obtain a higher ZT due to the flat corrugated bands and narrow peaks in their DOS. Meanwhile, the 2D PbTe violates HD theory due to the flatter bands it exhibits, while 2D SiGe possesses a small gap Dirac-cone band.

show abstract

Thermoelectric properties of Mexican-hat band structures

Cited by 6 publications

References 25 publications

Reveal Ultrafast Electron Relaxation across Sub-bands of Tellurium by Time- and Energy-Resolved Photoemission Microscopy

Reveal Ultrafast Electron Relaxation across Sub-bands of Tellurium by Time- and Energy-Resolved Photoemission Microscopy

Thermoelectric properties of monolayer and bilayer buckled XTe (X = Ge, Sn, and Pb)

Non-universal scaling of thermoelectric efficiency in 3D and 2D thermoelectric semiconductors

Contact Info

Product

Resources

About