Electric field driven reconfigurable multistable topological defect patterns

Saša Harkai (Avtor), Bryce S. Murray (Avtor), Charles Rosenblatt (Avtor), Samo Kralj (Avtor)

Povzetek

Topological defects appear in symmetry breaking phase transitions and are ubiquitous throughout Nature. As an ideal testbed for their study, defect configurations in nematic liquid crystals (NLCs) could be exploited in a rich variety of technological applications. Here we report on robust theoretical and experimental investigations in which an external electric field is used to switch between predetermined stable chargeless disclination patterns in a nematic cell, where the cell is sufficiently thick that the disclinations start and terminate at the same surface. The different defect configurations are stabilized by a master substrate that enforces a lattice of surface defects exhibiting zero total topological charge value. Theoretically, we model disclination configurations using a Landau-de Gennes phenomenological model. Experimentally, we enable diverse defect patterns by implementing an in-house-developed atomic force measurement scribing method, where NLC configurations are monitored via polarized optical microscopy. We show numerically and experimentally that an “alphabet” of up to 18 unique line defect configurations can be stabilized in a 4 × 4 lattice of alternating �=±1 surface defects, which can be “rewired” multistably using appropriate field manipulation. Our proof-of-concept mechanism may lead to a variety of applications, such as multistable optical displays and rewirable nanowires. Our studies also are of interest from a fundamental perspective. We demonstrate that a chargeless line could simultaneously exhibit defect-antidefect properties. Consequently, a pair of such antiparallel disclinations exhibits an attractive interaction. For a sufficiently closely spaced pair of substrate-pinned defects, this interaction could trigger rewiring, or annihilation if defects are depinned.

Ključne besede

line defects;topological defects;nematic liquid crystals;electric field;atomic force microscopy;numerical techniques;polarized optical microscopy;

Podatki

Jezik:	Angleški jezik
Leto izida:	2020
Tipologija:	1.01 - Izvirni znanstveni članek
Organizacija:	UM FNM - Fakulteta za naravoslovje in matematiko
Založnik:	American Phyisical Society
UDK:	53
COBISS:	33256487
ISSN:	2643-1564
Št. ogledov:	0
Št. prenosov:	0
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Slovenski jezik
Sekundarne ključne besede:	linijske napake;topološke napake;nematski tekoči kristali;električno polje;mikroskop na atomsko silo;numerične metode;optična polarizacijska mikroskopija;
Vrsta dela (COBISS):	Znanstveno delo
Strani:	str. 0131761-1-013176-14
Letnik:	ǂVol. ǂ2
Zvezek:	ǂno. ǂ1
Čas izdaje:	2020
DOI:	10.1103/PhysRevResearch.2.013176
ID:	25400524