Kai-Xuan Zhang va hamkasblari van der Waals antiferromagnit Co₁/₃TaS₂ ichidagi topologik spin xiralligini faqat elektr toki yordamida ikki qarama-qarshi holat orasida almashtirish mumkinligini eksperimental ravishda ko‘rsatdilar. Co₁/₃TaS₂ noncoplanar tetrahedral 3Q antiferromagnit spin tuzilmasida bir xil ishorali scalar spin chirality olib yuruvchi atom miqyosidagi tuzilma hosil qiladi; bu xirallik elektronlarning real-space Berry phase va topological Hall response ini belgilaydi. Tadqiqotchilar alohida heavy-metal spin-current layer ishlatmasdan tayyorlagan Co₁/₃TaS₂ nanodevicesda tashqi magnit maydon qo‘llamasdan writing-current pulses bilan Hall resistance ni ikki barqaror daraja o‘rtasida reversible tarzda o‘zgartirdilar. Birinchi deviceda switching taxminan 2,4–2,7 mA atrofida tugagani, critical current density taxminan 1,8 × 10⁶ A/cm² ekani va effect ikkinchi alohida deviceda ham takrorlangani bildirildi. Current switching faqat taxminan 25 K Néel temperature dan pastda kuzatildi va 40 K da yo‘qoldi; bu temperature dependence effect antiferromagnit spin order bilan bog‘liqligini qo‘llab-quvvatlaydi. Mualliflar mechanismni Co₁/₃TaS₂ ning broken crystal symmetries va Berry curvature bilan bog‘liq intrinsic self-spin-orbit torque orqali tushuntiradilar. Biroq spin chirality switching paytida direct magnetic imaging bilan kuzatilmagan, state Hall response orqali o‘qilgan va tajriba cryogenic temperatures bilan cheklangan.

Turkiya nuqtayi nazaridan tadqiqotning to‘g‘ridan-to‘g‘ri texnologik yoki sanoat mahsuloti natijasi yo‘q. Shunga qaramay, quantum materials, antiferromagnetic spintronics va low-energy memory research uchun muhim metodologik misol beradi: murakkab va topologik antiferromagnit spin texture tashqi magnetic field yoki alohida SOT-generating layer bo‘lmasdan elektrik ravishda boshqarilishi mumkin. Buni real device technology ga aylantirish uchun ancha yuqori operating temperature, pastroq switching current, long-term cycling endurance, switching speed, bit-to-bit reproducibility va scalable manufacturing kabi muammolar alohida hal qilinishi kerak.

Spin xiralligi nima?

Spin xiralligi magnit tuzilma ichidagi spinlar faqat qaysi yo‘nalishga qarashini emas, balki bir-biriga nisbatan hosil qiladigan uch o‘lchamli “qo‘llilik”ni ifodalaydi. Noncoplanar uch-spinli klassik modelda scalar spin chirality:

\[ \chi=\langle \mathbf{S}_1\cdot(\mathbf{S}_2\times\mathbf{S}_3)\rangle \]

ko‘rinishida ifodalanadi.

Bu yerda \(\mathbf{S}_1\), \(\mathbf{S}_2\) va \(\mathbf{S}_3\), triangular plaquette ustidagi uch spin vector. Agar uch spin bir tekislikda bo‘lmasa, vector triple product noldan farqli bo‘lishi mumkin va system positive yoki negative chiralityga ega bo‘lishi mumkin.

Bu quantity faqat geometrik ta’rif emas. Elektron bunday noncoplanar spin structure dan o‘tganda wave function qo‘shimcha real-space Berry phase olishi mumkin. Elektron nuqtayi nazaridan bu phase effective yoki emergent magnetic field — boshqacha aytganda gauge flux — kabi ishlashi mumkin.

Bu emergent field elektron harakatini yon tomonga og‘dirib, normal va anomal Hall contributionsdan alohida topological Hall effect hosil qilishi mumkin.

Nega chirality ishorasi muhim?

Uchala spin ham time reversal ostida aylantirilganda:

\[ \mathbf{S}_i \rightarrow -\mathbf{S}_i \]

bo‘ladi va scalar chirality ishorasi ham teskari bo‘ladi:

\[ \chi \rightarrow -\chi \]

Shu bilan birga chiralityga bog‘liq emergent gauge flux yo‘nalishi ham teskari bo‘ladi. Demak, ikki time-reversed spin configuration prinsipda topologik ma’lumotni ifodalashi mumkin bo‘lgan ikki alohida magnetic state hosil qilishi mumkin.

Tadqiqotning asosiy g‘oyasi aynan shu ikki holatni elektr toki bilan oldinga–orqaga aylantirishdir.

Figure 1 nimani ko‘rsatadi?

Tadqiqotning birinchi asosiy schematic uch-spinli uchburchak tuzilma orqali ikki qarama-qarshi chirality state ni ko‘rsatadi. Spin directions teskari aylantirilganda chirality sign va unga bog‘liq gauge flux ham teskari bo‘ladi.

Sxemaning yuqori va pastki qismlaridagi current circuits mualliflar ko‘zlagan control mechanismni ifodalaydi: current directionni o‘zgartirish bilan spin structure va shu orqali topological chiralityni ikki holat orasida elektrik ravishda switching qilish.

Bu figure direct experimental data emas; tadqiqot keyin sinagan fizik control conceptni belgilaydi.

Nega Co₁/₃TaS₂ tanlandi?

Co₁/₃TaS₂ bir nechta xususiyatni bir materialda birlashtiradi:

• van der Waals layered crystal structure,
• metallic antiferromagnetism,
• inversion va mirror symmetries buzilgan crystal geometry,
• topological electronic bands bilan bog‘liq kuchli Berry curvature,
• noncoplanar tetrahedral 3Q spin order,
• measurable topological Hall response.

Co atomsning TaS₂ layers orasidagi van der Waals gapga joylashishi pristine 2H-TaS₂ dagi centrosymmetric structure ni o‘zgartirib, Co₁/₃TaS₂ da non-centrosymmetric va mirror symmetries olib tashlangan crystal structure hosil qiladi.

Mualliflar bu symmetry breaking elektr toki bilan spin-orbit torque hosil qilish uchun muhimligini ta’kidlaydilar.

3Q holati nima?

Co₁/₃TaS₂ dagi topologik antiferromagnetic structure bitta spin modulation bilan emas, uch xil wave vector superpositioni bilan tavsiflanadi:

\[ Q_1=(1/2,0,0) \]

\[ Q_2=(0,1/2,0) \]

\[ Q_3=(1/2,-1/2,0) \]

Shu sabab tuzilma 3Q state deb ataladi.

Hosil bo‘lgan to‘rt-spinli tetrahedral fundamental structure ichida ikkita triangular spin cell mavjud va ikkalasi ham bir xil ishorali scalar chiralityga ega. Shu sabab chirality kristal ichida bir-birini cancel qilmaydi; net topological gauge flux va kuchli Hall response yuzaga kelishi mumkin.

Figure 2 ning asosiy xabari nima?

Figure 2 to‘rtta muhim pointni birlashtiradi:

1. Co atoms TaS₂ layers orasiga joylashgan crystal structure.
2. Tetrahedral 3Q spin structure ichida bir xil ishorali chiralityga ega triangular spin cells.
3. Bir-birining time-reversal pairi bo‘lgan positive va negative chirality states.
4. External magnetic field sweep qilinganda topological Hall resistance da ko‘rinadigan hysteresis.

Oxirgi observation ikki chirality state elektr toki qo‘llanmasdan oldin magnetic field bilan bir-biriga aylantirilishi mumkinligini ko‘rsatuvchi reference bo‘lib xizmat qiladi.

Nega antiferromagnet ishlatish qiziqarli?

Antiferromagnetsda qo‘shni magnetic momentsning katta qismi bir-birini kompensatsiya qilgani sabab net magnetization juda kichik yoki nolga yaqin bo‘lishi mumkin. Bu xususiyat low stray field, high information density va fast spin dynamics nuqtayi nazaridan spintronics uchun jozibali.

Biroq ayni xususiyat antiferromagnetic spin statesni external magnetic fields bilan control qilishni ham qiyinlashtiradi. Co₁/₃TaS₂ dagi structure yana simple two-sublattice antiferromagnet emas, balki four-spin complex topological 3Q texture.

Shu sabab tadqiqotning muhim jihati shunchaki “current bilan magnet flip qilindi” degan natija emas, balki complex topological antiferromagnetic chiralityning electric switchingidir.

Spin-orbit torque qanday ishlaydi?

Klassik spin-orbit torque yoki SOT architectureda heavy-metal layerdan o‘tkazilgan charge current spin Hall effect orqali spin current hosil qiladi. Bu spin current qo‘shni magnetic layerga kirib magnetic momentga torque beradi.

Co₁/₃TaS₂ tajribasida bunday separate spin-source heavy-metal layer ishlatilmagan. Mualliflar elektr toki materialning o‘z electronic structure ichida hosil qiladigan torqueni intrinsic self-SOT deb ataydilar.

Taklif qilingan physical picturega ko‘ra, Co₁/₃TaS₂ ning non-centrosymmetric structure, broken mirror symmetries va Berry curvature elektr toki orqali material ichida spin angular momentum hosil bo‘lishiga imkon beradi.

Self-SOT bevosita o‘lchandimi?

Tadqiqotning experimental evidence self-SOT torque coefficientning direct spectroscopic measurementi emas. Evidence chain quyidagicha:

• Co₁/₃TaS₂ o‘zida topological 3Q antiferromagnetic structurega ega.
• Deviceda separate SOT heavy-metal layer yo‘q.
• Switching paytida external magnetic field qo‘llanmaydi.
• Current polarity Hall stateni ikki yo‘nalishda o‘zgartiradi.
• Yangi state current olib tashlangandan keyin saqlanadi.
• Effect Néel temperature dan pastda bor, yuqorida yo‘qoladi.
• Ayni behavior ikkinchi deviceda qayta olinadi.

Mualliflar bu combined observationsni intrinsic self-SOT-induced spin-chirality switchingga evidence sifatida talqin qiladilar.

Birinchi device qanday o‘lchandi?

Figure 3a Co₁/₃TaS₂ nanoflake devicening optical image va electrical readout schemani ko‘rsatadi.

Experiment ikki bosqichli:

1. Writing: Nisbatan high-current qisqa pulse qo‘llanib spin state o‘zgartiriladi.
2. Reading: Writing pulse olib tashlangandan so‘ng kichik read current bilan transverse Hall resistance \(R_{xy}\) o‘lchanadi.

Bu method switching current olib tashlangandan keyin state saqlanadimi yoki yo‘qmi, shuni aniqlash imkonini beradi.

Nega Hall resistance ishlatiladi?

Co₁/₃TaS₂ da topological 3Q spin chirality real-space Berry phase orqali topological Hall effect hosil qiladi. Chirality sign o‘zgarganda emergent gauge flux direction ham o‘zgargani sabab Hall response sign yoki level chirality state ni electric readout uchun ishlatilishi mumkin.

Shu sabab tadqiqot chiralityni direct real-space magnetic microscopy bilan emas, \(R_{xy}\) signal orqali kuzatadi.

Néel temperature qancha?

Hall hysteresis taxminan:

\(T_N \sim 25\) K

dan pastda yuzaga keladi.

Figure 3c da 5, 10, 15 va 20 K kabi low temperaturesda clear Hall hysteresis ko‘rinadi; temperature 25 K va yuqoriga yaqinlashganda bu behavior susayadi yoki yo‘qoladi.

Bu result exfoliated nanoflake bulk materialdan ma’lum topological 3Q antiferromagnetic state ni device fabricationdan keyin ham saqlashini qo‘llab-quvvatlaydi.

Current bilan haqiqatan ikki alohida state hosil qilindimi?

Ha. 15 K nominal temperatureda o‘lchangan \(R_{xy}\)-writing current curve clear hysteresis ko‘rsatadi.

Current bir directionda oshirilganda Hall resistance bir stable levelga o‘tadi, opposite-direction current pulse esa systemni boshqa stable levelga olib boradi. Current olib tashlangandan keyin Hall level saqlanadi.

Shu sabab tadqiqot behaviorni:

• reversible — qaytariladigan,
• nonvolatile — saqlanib qoluvchi,
• field-free — switching vaqtida magnetic fieldsiz

deb ta’riflaydi.

“Magnetic fieldsiz” aynan nimani anglatadi?

Maqoladagi barcha experiments hech qachon magnetic field ishlatilmasdan bajarilmagan. Avval \(R_{xy}-H_z\) measurementsda topological Hall hysteresisni characterize qilish uchun external magnetic field qo‘llangan.

“Magnetic-field-free switching” ifodasi current writing/switching operation vaqtida external magnetic field ishlatilmaganini anglatadi.

Bu farq technological meaning nuqtayi nazaridan muhim.

Joule heating qanday nazorat qilindi?

High writing current nanoflakeni Joule heating orqali qizdirishi mumkin. Agar sample \(T_N\) dan yuqoriga chiqib keyin sovisa, ko‘rilgan state change faqat torquedan emas, thermal reorderingdan kelishi mumkin edi.

Tadqiqotchilar shuning uchun resistance–temperature va resistance–current calibrationsni taqqoslaganlar.

Main textda reported result:

• nominal temperature: 15 K,
• 3,7 mA current: sampleni maximum taxminan 25 K ga, ya’ni \(T_N\) ga olib chiqishi mumkin,
• field-free switching experimentsdagi maximum current: 3,3 mA.

Shu sabab mualliflar measurement vaqtida sample antiferromagnetic ordering temperaturedan pastda qolganini ta’kidlaydilar.

Switching paytida real temperature qancha edi?

Birinchi deviceda switching taxminan 2,4–2,7 mA atrofida tugagani aytilgan. Joule-heating calibrationga ko‘ra, bu currentda sample temperature taxminan:

20 K

deb baholanadi.

Shu sabab graphdagi “15 K” nominal cryostat temperature; active writing pulse paytida nanoflakening o‘z temperaturei yuqoriroq bo‘lishi mumkin.

Hall switching magnitude qancha edi?

Current switching paytida Hall resistance change taxminan:

0,01 Ω

deb beriladi.

Zero-field Hall resistance taxminan:

• 15 K da 0,04 Ω,
• 20 K da 0,012 Ω

bo‘lgani sabab source Joule heating qaysi temperature reference bilan baholanishiga qarab switching rationi:

\[ 0{,}01/0{,}04=25\% \]

bilan:

\[ 0{,}01/0{,}012=83{,}3\% \]

orasida hisoblaydi.

Bu ikki percentage ikki separate independent device result emas; ayni switching magnitude ikki different temperature reference bo‘yicha normalizationidir.

Switching temperaturega qanday bog‘liq?

Figure 3e dagi temperature series current-induced Hall hysteresis low temperaturesda mavjudligini va \(T_N\) ga yaqinlashganda yo‘qolishini ko‘rsatadi.

Bu behavior muhim, chunki agar gap faqat contact resistance, oddiy electromigration yoki temperature-independent electrical memory effect haqida bo‘lganida, signal aynan antiferromagnetic transition temperature atrofida yo‘qolishi kutilmasligi mumkin edi.

Shu sabab temperature test switchingning magnetic originini tekshiruvchi kuchli control experiment hisoblanadi.

Nega ikkinchi device muhim?

Bitta nanoflakedagi hysteresis device defect, contact geometry yoki o‘ziga xos local statedan kelishi mumkin edi. Shu sabab tadqiqotchilar ikkinchi pristine Co₁/₃TaS₂ device tayyorlab, ayni experimental sequence ni takrorladilar.

Ikkinchi deviceda ham:

• metallic transport behavior,
• 25 K dan past topological Hall hysteresis,
• 15 K atrofida current-induced Hall-state switching,
• external magnetic fieldsiz bidirectional transition

kuzatildi.

40 K da esa writing current sweep qilinsa ham chirality-switching signal olinmadi.

Figure 4 nimani tasdiqlaydi?

Figure 4 tadqiqotning asosiy natijasi bitta devicega xos tasodifiy observation emasligini ko‘rsatuvchi independent replication hisoblanadi.

Ayniqsa 40 K dagi flat \(R_{xy}\)-current curve antiferromagnetic order bo‘lmagan temperatureda ayni electrical current protocol o‘z-o‘zidan hysteretic Hall memory yaratmasligini ko‘rsatadi.

Nega curves butunlay silliq emas?

Figure 3 va Figure 4 da switching threshold atrofida ayrim dip, peak va step-like structures ko‘rinadi.

Mualliflar bular:

• chirality/magnetic domain nucleation,
• domain annihilation,
• domain-wall motion,
• pinning,
• multistep metastable transitions

bilan bog‘liq bo‘lishi mumkinligini taklif qiladilar.

Biroq tadqiqot bu domainsni direct imaging qilmagan. Shu sabab fluctuations domain dynamicsdan keladi degan izoh physically plausible author interpretation, lekin direct imaging evidence emas.

Critical current density qancha?

Source critical switching current density ni taxminan:

1,8 × 10⁶ A/cm²

deb hisoblaydi.

Mualliflar bu value recent high-efficiency SOT switching studiesdagi values bilan comparable yoki undan past ekanini ta’kidlaydilar.

Biroq tadqiqotda single-bit switchingning real energy consumptioni joule bilan o‘lchanmagan. Shu sabab critical current density energy efficiency uchun foydali, ammo to‘liq bo‘lmagan indicator.

Tadqiqot qo‘llab-quvvatlaydigan natijalar

• Co₁/₃TaS₂ nanoflakelarda topological 3Q antiferromagnetic Hall state taxminan 25 K dan pastda saqlanadi.
• Writing-current pulses Hall resistance ni ikki nonvolatile state orasida reversible tarzda o‘zgartira oladi.
• Switching vaqtida external magnetic field talab qilinmaydi.
• Magnetic layerga adjacent alohida heavy-metal SOT source ishlatilmagan.
• Current-induced switching ikkinchi independent Co₁/₃TaS₂ deviceda qayta olingan.
• Effect taxminan Néel temperatureda yo‘qoladi.
• 40 K da ayni writing-current protocol chirality switching hosil qilmaydi.
• Critical switching current density taxminan 1,8 × 10⁶ A/cm².
• Source resultsni Co₁/₃TaS₂ ichida intrinsic self-SOT-induced chirality switching sifatida talqin qiladi.

Tadqiqot hali isbotlamagan natijalar

• Topological spin chirality room temperatureda switching qilinishi ko‘rsatilmagan.
• Functionality faqat taxminan 25 K dan past antiferromagnetic phase da ko‘rsatilgan.
• Spin/chirality domains switching vaqtida direct imaging qilinmagan.
• Self-SOT magnitude independent torque spectroscopy bilan direct o‘lchanmagan.
• Hall signaldagi steps aynan domain-wall motiondan kelgani isbotlanmagan.
• Long-term switching endurance yoki millionlab write cycles sinovdan o‘tkazilmagan.
• Switching speed nanosecond yoki picosecond scale da aniqlanmagan; experimentda 1-second current pulses ishlatilgan.
• Real memory-cell density, error rate yoki retention time characterize qilinmagan.
• Single-switching real energy consumption direct o‘lchanmagan.
• Result barcha skyrmion yoki noncoplanar antiferromagnetsga bir xil tarzda generalize qilinishi experimental ko‘rsatilmagan.

Tadqiqot Usuli va Natijalari

Single crystals qanday sintez qilindi?

Co₁/₃TaS₂ single crystals ikki bosqichli method bilan tayyorlangan.

Avval:

• Co purity: >%99,99,
• Ta purity: >%99,99,
• S purity: >%99,99

bo‘lgan starting materials mos ratiosda maydalangan va evacuated quartz ampoulega sealed qilingan.

Aralashma:

900°C da 10 kun

solid-state reactionga uchratilgan.

Bu bosqichning maqsadi chemically more homogeneous polycrystalline precursor olish.

Crystal growth qanday bajarildi?

Tayyorlangan precursor chemical vapor transport yoki chemical vapor transport (CVT) method bilan single crystalga aylantirilgan.

Transport agent sifatida:

4,5 mg I₂/cm³

iodine ishlatilgan.

Quartz tube two-zone furnace da:

960°C → 840°C

temperature gradientda:

2 hafta

ushlab turilgan.

Crystals structural characterizationida XRD va Raman spectroscopy ishlatilgani bildiriladi.

Nanodevice qanday ishlab chiqarildi?

Co₁/₃TaS₂ crystals mechanical exfoliation bilan SiO₂/Si waferga transfer qilinib, electrical transport uchun mos nanoflake tanlangan.

Device fabrication steps:

1. PMMA A7 resist nanoflake ustiga 4000 rpm da spin coating bilan qoplangan.
2. 130°C da 1,5 minute post-bake qo‘llangan.
3. Electrode geometry electron-beam lithography bilan yaratilgan.
4. Electron-beam evaporation bilan 80/10 nm Au/Ti electrodes deposit qilingan.

Demak “separate heavy-metal layer yo‘q” degan ifoda electrodes metal emas degani emas. Au/Ti electrical contacts mavjud; yo‘q component magnetic layerga torque berish uchun mo‘ljallangan separate heavy-metal spin Hall layerdir.

Electrical measurements qanday bajarildi?

Transport measurements custom-built closed-loop resistance setup va commercial cryogenic system yordamida bajarilgan.

Source measurement instruments sifatida:

• Keithley 6220,
• Keithley 2182,
• lock-in amplifier

ni ko‘rsatadi.

Topological Hall characterizationda \(R_{xy}-H_z\) curves samplega out-of-plane magnetic field qo‘llab o‘lchangan.

Writing va reading timing

Switching experimentda writing-current pulse duration:

1 soniya

deb berilgan.

Pulse tugagandan keyin Hall signal o‘lchanishidan oldin:

10 soniya

kutilgan.

Bu measurement protocol writing current endi qo‘llanmayotgan bo‘lsa ham yangi Hall level saqlanadimi, shuni test qiladi.

Asosiy experimental resultsning technical summarysi

Joule-heating interpretive limit

Main article Joule heating uchun ishlatilgan detailed \(R_{xx}-I\) calibration Supporting Information Figure S4 da joylashganini bildiradi. Mavjud source filega Supporting Information qo‘shilmagan.

Shu sabab Verianla faqat main articleda ochiq reported calibration resultsni beradi; S4 dagi raw curves independently qayta o‘qilmagan.

Hall readout interpretive limit

Tadqiqotning electrical readout logic Co₁/₃TaS₂ ning topological 3Q state da topological Hall response chirality sign bilan bog‘liqligiga asoslanadi.

Bu approach kuchli electrical proxy beradi; biroq Hall-resistance change real spacedagi barcha spinlar microscopic jihatdan qanday rearrange bo‘lganini o‘z-o‘zidan ko‘rsatmasligini unutmaslik kerak.

Ayniqsa switching threshold atrofidagi steps uchun domain-dynamics interpretation direct domain imaging bilan validate qilinmagan.

Tadqiqotning kuchli tomonlari

• Topological spin chiralityning electrical controliga bevosita qaratilgan aniq experimental design.
• Separate heavy-metal SOT layersiz device fabrication.
• Magnetic fieldsiz writing-current switching.
• Nonvolatile electrical readout protocol.
• Temperature control bilan magnetic originni test qilish.
• Joule heatingga maxsus calibration.
• Second independent deviceda result replication.
• 40 K negative-control experiment.
• Material crystal symmetry, Berry curvature va 3Q topological spin structure ni bitta mechanistic frameworkda birlashtirish.

Asosiy limitations

• Operating temperature taxminan 25 K dan past bilan cheklangan.
• Test qilingan independent device count main textda cheklangan.
• Long-term endurance va retention study reported emas.
• 1-second writing pulse ishlatilgani sabab real minimum switching time aniqlanmagan.
• Self-SOT magnitude separate torque measurement bilan direct chiqarilmagan.
• Spin-chirality domains direct imaging qilinmagan.
• Joule heating butunlay yo‘q emas; model/calibration bilan nazorat qilingan.
• Supporting Information current upload ichida yo‘qligi sabab supporting figures independently ko‘rib chiqilmagan.
• Real device-level energy-per-operation measurement berilmagan.
• Technology room temperaturega ko‘chirilishi experimental ko‘rsatilmagan.

Manba va Usul Haqida Izoh

To‘liq original study title: Current Switching of Topological Spin Chirality in the van der Waals Antiferromagnet Co1/3TaS2

Authors: Kai-Xuan Zhang; Seungbok Lee; Woonghee Cho; Je-Geun Park.

Corresponding authors: Kai-Xuan Zhang va Je-Geun Park.

Equal-first/equal contribution: Source equal contribution yoki equal-first-authorship statement bermaydi.

Institutions: Department of Physics and Astronomy, Seoul National University; Center for Quantum Materials, Department of Physics and Astronomy, Seoul National University; Institute of Applied Physics, Seoul National University, Seoul, South Korea.

DOI:10.1002/adma.202522943

Journal: Advanced Materials.

Volume / issue / article number: 38(19), e22943.

Publisher: Wiley-VCH GmbH.

Source type va peer-review status: Peer-reviewed experimental research article.

Received: 18 November 2025.

Revised: 10 February 2026.

Accepted: 2 March 2026.

First online publication: 6 March 2026.

Official publication link:Wiley Online Library

License: Creative Commons Attribution License. Article open access.

Funding: Samsung Science & Technology Foundation, Grant No. SSTF-BA2101-05; National Research Foundation of Korea Leading Researcher Program, Grant No. RS-2020-NR049405.

Conflict of interest: Authors declare no conflict of interest.

Data availability: Data supporting findings are stated to be available from corresponding author upon reasonable request.

Author contributions / CRediT: Main source does not contain separate CRediT or detailed individual-author contribution section.

Method note on “heavy-metal-free” expression

In the study, “heavy-metal-free switching” is used in SOT-architecture context: there is no separate heavy-metal layer designed to inject spin current into Co₁/₃TaS₂. However, electrical contacts of device are 80/10 nm Au/Ti electrodes produced by electron-beam evaporation. Thus the phrase does not mean all metallic elements in device are light metals.

Interpretive limit on self-SOT mechanism

The study experimentally demonstrates current switching in pristine Co₁/₃TaS₂ without magnetic field and without separate spin-source layer. Authors attribute this to intrinsic self-SOT associated with non-centrosymmetric crystal structure, broken mirror symmetries, topological bands and strong Berry curvature.

However, torque magnitude was not directly measured by an independent torque-metrology method. Therefore Verianla presents self-SOT as mechanism proposed by the study and supported by experimental observations.

Limit on chirality measurement

Chirality reversal was not tracked with direct real-space spin-imaging method. Chirality state is electrically read through Hall response arising from 3Q topological spin order of Co₁/₃TaS₂.

This does not invalidate the main result, but it does not support a stronger claim that “every spin vector was directly observed during switching”.

Joule heating and Supporting Information note

Source bases detailed Joule-heating calibration on Figure S4 in Supporting Information. Since uploaded main article does not contain Supporting Information file, supporting figure was not independently viewed in Verianla review. Only estimates explicitly reported in main source — 3,7 mA → approximately 25 K and 2,4–2,7 mA → approximately 20 K — were used.

Energy-efficiency note

Authors’ “high energy efficiency” assessment is based on comparing critical switching current density of approximately 1,8 × 10⁶ A/cm² with high-efficiency SOT systems in literature. Source does not report a separate energy-per-switch or full electrical power-consumption analysis. Therefore Verianla does not present the result as measured product-level energy consumption.

Scientific interpretive limit

The study provides strong experimental evidence that a topological antiferromagnetic chirality state can be controlled by electric current in a field-free and nonvolatile manner. However, experimental operating temperature is below approximately 25 K, and the result in its current form does not mean a room-temperature commercial chiral-spintronics memory technology.

Authors suggest that the approach could be extended to other skyrmion systems and noncoplanar magnets. This is a future-looking physical generalization proposal; the current study did not experimentally test the same switching mechanism in other materials.

The physical mechanisms, device results, temperatures, currents and Hall data in this Verianla article are based on the uploaded original study. External sources were used only for bibliographic verification of publication identity, volume/issue information, first online publication date and Advanced Materials peer-review process; no new experimental spintronics result was added from outside.