Competition between Stepwise Polarization Switching and Chirality Coupling in Ferroelectric GeS Nanotubes

Abstract

The ferroelectricity of group-IV chalcogenides $MX$ ($M$=Ge, Sn; $X$=Se, S) monolayers has been extensively investigated, but how the ferroelectricity evolves in their one-dimensional nanotubes remains largely unclear. Employing an accurate deep-learning interatomic potential of first-principles precision, we uncover a general stepwise mechanism for polarization switching in zigzag and chiral GeS nanotubes, which has an energy barrier that is substantially lower than the one associated with the conventional one-step switching mechanism. The switching barrier (per atom) gradually decreases as increasing the number of intermediate steps and converges to a value that is almost independent of the tube diameter.

Giant In-Plane Flexoelectricity and Radial Polarization in Janus IV–VI Monolayers and Nanotubes

“…These and other fascinating properties drive the interest of the community to search for more compositions and crystal structures that can form Janus 1D nanotubes with small radii and novel properties arising from the spontaneous wrapping of the 2D sheet into a tube. The class of 2D group IV–IV monochalcogenides (as illustrated in Figure a) show strong mechanical and electronic anisotropy and giant in-plane spontaneous polarization, ,, and have properties interesting for electronic and optoelectronic applications, Their Janus form, e.g., PbSnS 2 , has recently emerged and brought new perspectives for electronic, thermoelectric, supercapacitors, and optoelectronics devices. − …”

Profiling Electronic and Phononic Band Structures of Semiconductors at Finite Temperatures: Methods and Applications

“…[1][2][3][4][5][6][7][8][9][10] Understanding the properties of semiconductors and the sophisticated microscopic processes and mechanisms that enable the excellent properties are thus at the core of modern semiconductors research. [2,[11][12][13][14][15][16][17] Among the basic properties of semiconductors, their electronic and phononic band structures are of key interest, since various functional properties such as optical absorption and emission, charge and heat transport coefficients, carrier recombination, and thermodynamic free energies can be derived from the basic band structures.…”

Vertical Dipole Dominates Charge Carrier Lifetime in Monolayer Janus MoSSe

“…Recently, a class of 2D materials with intrinsic vertical dipoles has attracted significant attention in the field of photocatalytic water splitting. , The introduction of intrinsic vertical dipoles not only effectively separates photogenerated electrons and holes on different surfaces of 2D materials but also expands the light absorption range for driving the water splitting reaction. Janus TMDs are a type of experimentally synthesizable 2D materials with asymmetric structures along the vertical direction. , The asymmetric structure in Janus TMDs introduces vertical dipole and other emergent properties, − and some of them have been predicted to be potential photocatalysts for water splitting. , Some studies have investigated the carrier dynamics in such materials, and nonadiabatic (NA) molecular dynamics (MD) simulations have shown that the introduction of a vertical dipole in Janus MoSSe leads to a larger carrier lifetime compared to that of MoS 2 . However, there is no systematic theoretical research focusing on the impact of vertical dipoles on carrier recombination situations in these 2D materials, especially the relationship between vertical dipoles and band gaps in influencing carrier lifetimes.…”