The interior bulk of a topological insulator is indeed an insulator, but electrons (spheres) move swiftly on the surface as if through a metal. They are spin-polarized, however, with their momenta (directional ribbons) and spins (arrows) locked together. Berkeley Lab researchers have discovered that the spin polarization of photoelectrons (arrowed sphere at upper right) emitted when the material is struck with high-energy photons (blue-green waves from left) is completely determined by the polarization of this incident light. (Image Chris Jozwiak, Zina Deretsky, and Berkeley Lab Creative Services Office)
Scientists from the Berkeley Lab discovered that when topological insulators are hit with a laser beam, the spin polarization of the electrons they emit can be completely controlled in three dimensions.
Plain-looking but inherently strange crystalline materials called 3D topological insulators (TIs) are all the rage in materials science. Even at room temperature, a single chunk of TI is a good insulator in the bulk, yet behaves like a metal on its surface.
Researchers find TIs exciting partly because the electrons that flow swiftly across their surfaces are “spin polarized”: the electron’s spin is locked to its momentum, perpendicular to the direction of travel. These interesting electronic states promise many uses – some exotic, like observing never-before-seen fundamental particles, but many practical, including building more versatile and efficient high-tech gadgets, or, further into the future, platforms for quantum computing.
A team of researchers from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California at Berkeley has just widened the vista of possibilities with an unexpected discovery about TIs: when hit with a laser beam, the spin polarization of the electrons they emit (in a process called photoemission) can be completely controlled in three dimensions, simply by tuning the polarization of the incident light.
“The first time I saw this it was a shock; it was such a large effect and was counter to what most researchers h cloud VMS ad assumed about photoemission from topological insulators, or any other material,” says Chris Jozwiak of Berkeley Lab’s Advanced Light Source (ALS), who worked on the experiment. “Being able to control the interaction of polarized light and photoelectron spin opens a playground of possibilities.”
The Berkeley Lab-UC Berkeley team was led by Alessandra Lanzara of Berkeley Lab’s Materials Sciences Division (MSD) and UC Berkeley’s Department of Physics, working in collaboration with Jozwiak and Zahid Hussain of the ALS; Robert Birgeneau, Dung-Hai Lee, and Steve Louie of MSD and UC Berkeley; and Cheol-Hwan Park of UC Berkeley and Seoul National University. They and their colleagues report their findings in Nature Physics.
Strange electronic states and how to measure them
In diagrams of what physicists call momentum space, a TI’s electronic states look eerily like the same kinds of diagrams for graphene, the single sheet of carbon atoms that, before topological insulators came along, was the hottest topic in the materials science world.
In energy-momentum diagrams of graphene and TIs, the conduction bands (where energetic electrons move freely) and valence bands (where lower-energy electrons are confined to atoms) don’t overlap as they do in metals, nor is there an energy gap between the bands, as in insulators and semiconductors. Instead the “bands” appear as cones that meet at a point, called the Dirac point, across which energy varies continuously.
The experimental technique that directly maps these states is ARPES, angle-resolved photoemission spectroscopy. When energetic photons from a synchrotron light source or laser strike a material, it emits electrons whose own energy and momentum are determined by the material’s distribution of electronic states. Steered by the spectrometer onto a detector, these photoelectrons provide a picture of the momentum-space diagram of the material’s electronic structure.
The diagram at right shows the electronic states of bismuth selenide in momentum space. ARPES, at left, can directly create such maps with photoelectrons. A slice through the conduction cone at the Fermi energy maps the topological insulator’s surface as a circle (upper left); here electron spins and momenta are locked together. Initial ARPES measurements in this experiment were made with p-polarized incident light in the regions indicated by the green circle and line, where the spin polarization of the photoelectrons is consistent with the intrinsic spin polarization of the surface.
Similar as their Dirac-cone diagrams may appear, the electronic states on the surface of TIs and in graphene are fundamentally different: those in graphene are not spin polarized, while those of TIs are completely spin polarized, and in a peculiar way.
A slice through the Dirac-cone diagram produces a circular contour. In TIs, spin orientation changes continuously around the circle, from up to down and back again, and the locked-in spin of surface electrons is determined by where they lie on the circle. Scientists call this relation of momentum and spin the “helical spin texture” of a TI’s surface electrons. (Electron spin isn’t like that of a spinning top, however; it’s a quantum number representing an intrinsic amount of angular momentum.)
Directly measuring the electrons’ spin as well as their energy and momentum requires an addition to ARPES instrumentation. Spin polarization is hard to detect and in the past has been established by firing high-energy electrons at gold foil and counting which way a few of them bounce; collecting the data takes a long time.
Jozwiak, Lanzara, and Hussain jointly led the development of a precision detector that could measure the spin of low-energy photoelectrons by measuring how they scatter from a magnetic surface. Called a spin time-of-flight analyzer, the device is many times more efficient at data collection.
Says Hussain, “It’s the kind of project that could only be done at a place like Berkeley Lab, where tight collaboration for a wide range of capabilities is possible.”
The new instrument was first used at the ALS to study the well-known topological insulator bismuth selenide. While the results confirmed that bismuth selenide’s helical spin texture persists even at room temperature, they raised a perplexing question.
Lanzara says, “In an ARPES experiment, it’s usually assumed that the spin polarization of detected photoelectrons accurately reports the spin polarization of electrons within the material.” She explains that “this assumption is frequently made when confirming the helical spin texture of a TI’s surface electrons. But in our spin-ARPES experiments, we found significant deviations between the spin polarizations of the surface electrons versus the photoelectrons. We knew we had to look further.”
Flipping photoelectron spins
Probing the TI surface electrons didn’t require the high photon energy of a synchrotron beam, so the new study was primarily done in a laboratory with a laser that could produce intense ultraviolet light capable of stimulating photoemission, and whose polarization was readily manipulated. The experiment used high-quality samples of bismuth selenide from Birgeneau’s MSD and UC Berkeley labs.
Incident light that’s p-polarized (upper left) produces photoelectrons consistent with the usual picture of spin polarization in a topological insulator’s surface, but changing the polarization of the incident light also changes the spin polarization of the photoelectrons.
In the first experiments, the incident light was p‑polarized, which means the electric part of the light wave was parallel to a plane that was perpendicular to the TI surface and oriented according to the path of the emitted photoelectrons. Since studies of topological insulators typically use p‑polarized light in this geometry, sure enough, the spin-ARPES measurements showed the photoelectrons were indeed spin polarized in directions consistent with the expected spin texture of the surface electrons.
“After we’d measured p‑polarization, we switched to an s‑polarized laser beam,” Jozwiak says. “It only took a few minutes to collect the data.” (S‑polarization means the electric part of the light wave is perpendicular to the same imaginary plane – perpendicular in German being senkrecht.)
Three minutes after he started the run, Jozwiak got a jolt. “The experiment was completely the same, except for the light polarization, but now the photoelectrons were spin polarized in the reverse direction – the opposite of what you’d expect.” His first assumption was “I must have done something wrong.”
Repeated careful experiments with a range of laser polariz industrial cellular modem ations showed, however, that the spin polarization of the wastewater treatment photons in the laser beam controlled the polarization of the emitted photoelectrons. When the laser polarization was smoothly varied – and even when it was circularly polarized right or left – the photoelectron spin polarization followed suit.
Why had no results counter to the expected surface textures been reported before? Probably because the most common kind of spin-ARPES experiment makes a few measurements in a typical geometry using p-polarized light. With other arrangements, however, photoelectron spin polarization departs markedly from expectations.
The team’s theory collaborators, Park, Louie, and Lee, helped explain the unusual theoretical results when they predicted that just such differences between photoelectron and intrinsic textures should occur. There are also suggestions that the simple picture of spin texture in topological insulators is more complex than has been assumed. Says Lanzara, “It’s a great motivation to keep digging.”
The ability to hit a topological insulator with a tuned laser and excite polarization-tailored electrons has great potential for the field of spintronics – electronics that exploit spin as well as charge. Devices that optically control electron distribution and flow would constitute a significant advance.
Optical control of TI photoemission has more immediate practical possibilities as well. Bismuth selenide could provide just the right kind of photocathode source for experimental techniques that require electron beams whose spin polarization can be exquisitely and conveniently controlled.
DOE’s Office of Science supports the ALS and supported this research.
Publication: Chris Jozwiak, et al., “Photoelectron spin-flipping and texture manipulation in a topological insulator,” Nature Physics (2013); doi:10.1038/nphys2572
Image: Chris Jozwiak, Zina Deretsky, and Berkeley Lab Creative Services Office;
Tags: cellular modem ethernet, 4g LTE router, 3g wireless router, 4g LTE router with SIM card, cellular router vendor, verizon 4g LTE router, best industrial wifi router, 4g modem router, 4g modem router wifi, att 4g router, cellular router wifi, industrial multi sim cellular router, m2m cellular router, verizon industrial router, 4g lte gateway, 4g lte modem, industrial cellular vpn router, industrial 3g m2m, industrial l2tp cellular router, industrial ethernet router, plc router, 12vdc lte router, 4g lte router dual SIM, multi SIM LTE router, cellular router manufacturer, edge gateway, industrial iot gateway, overhead line sensor, distribution line sensor, distribution line fault detection, medium voltage smart grid sensor, MV smart grid sensor, smart grid sensor, power line sensor, power sensor, MV sensor, Grid Fault Detection, Line Monitoring, Grid Analytics, Predictive Grid Analytics, Grid Monitoring, Grid Analytics System, Power Fault Detection, Advanced Grid Analytics, Intelligent Line Monitoring, distribution fault detection, smart vending machine, smart vending solutions, QR code vending machine, telemetry vending machine, intelligent vending machine, touch screen for vending machine, vending software, cashless vending, coupon vending machine, iot vending machine, vending machine card reader, POS vending machine, smart vending machine software, credit card vending machine, Industrial router, cellular router, 4g router, LTE router, 3g router, M2M router, wireless router, wireless m2m router, wireless m2m, Industrial Wireless M2M, Industrial Wireless M2M Router, Industrial Wireless M2M products, M2M wireless producdts, WiFi M2M Router, Industrial Wireless M2M gateway, industrial IoT router, industrial IoT gateway, industrial LTE router, Industrial router, cellular router, 4g router , LTE router, 3g router , M2M router, wireless router, wireless m2m router, WiFi M2M Router, Industrial Wireless M2M Router, M2M IoT router, industrial wireless router, industrial M2M router, industrial LTE router, Industrial VPN router, Dual SIM M2M router, M2M gateway, IoT gateway, Industrial router, low cost industrial router , low cost cellular router, low-cost LTE router, low-cost M2M router, compact industrial router, low-cost cellular router , cellular router, low-cost 4g router , LTE router, 3g router , M2M router, wireless router, wireless m2m router, WiFi M2M Router, Industrial Wireless M2M Router, M2M IoT router, industrial wireless router, industrial M2M router, industrial LTE router, Industrial VPN router, Dual SIM M2M router, M2M gateway, IoT gateway, LTE Cat 1 router, Embedded LTE Cat 1 router, Industrial LTE Cat 1 router, Verizon Embedded modem, Verizon Embedded router, Overhead Line Monitoring, Distribution Power Line Monitoring, Grid Analytics System, overhead Line sensor, grid fault detection, distribution Line Monitoring, grid fault location, Smart Vending, touchscreen vending, cashless vending, cloud VMS, vending retrofit, smart vending solution, vending vms, cashless payment, vending route optimization, vending inventory management, vending retrofit, vending PC, vending computer, Android vending computer, vending computer, Android vending computer, Android industrial computer, 崀山, 崀山科技, 崀山科技全球服务中心, LangShan Technology Global Service Center, LangShan Technology, LangShan, china webdesign, seo, web design, 企业建站, 外贸商城, 网站推广, 技术兼职, 技术支援, 技术支持, SEO, joomla template, joomla webdesign, joomla web design, joomla seo, wordpress themes, wordpress webdesign, wordpress web design, wordpress seo, magento themes, magento webdesign, magento web design, magento seo, opencart themes, opencart webdesign, opencart web design, opencart seo, prestashop themes, prestashop webdesign, prestashop web design, prestashop seo, 崀山, 崀山科技, 崀山科技全球服务中心, LangShan Technology Global Service Center, LangShan Technology, LangShan, china webdesign, seo, web design, 企业建站, SEO, joomla template, joomla webdesign, joomla web design, joomla seo, wordpress themes, wordpress webdesign, wordpress web design, wordpress seo, magento themes, magento webdesign, magento web design, magento seo, opencart themes, opencart webdesign, opencart web design, opencart seo, prestashop themes, prestashop webdesign, prestashop web design, prestashop seo, wordpress shop, wordpress plugins, wordpress plugins shop, lte, 4g, 4g-lte, 3g, umts, dsl, ethernet, cellular, gprs, wireless, wired, wi fi, vpn, m2m vpn, openvpn, ipsec-vpn, secure, reliable, dual sim, 2 sim, redundant, rugged, din rail, din rail mounting, ul certified, fcc certified, ptcrb certified, verizon wireless certified, att certified, ce certified-, emark certified, azure iot certified, cost effective, ipv6, python programming, reliability, security, high-speed, lte cat 1, router, gateway, routers, cellular gateway, modem, hardware, software, cloud platform, applications, ethernet switch, managed switch, vehicle router, car router, dtu, data terminal unit, computer, vending computer, vending pc, manufacturer, manufacturing, android computer, iot, industrial iot, industrial internet of things, m2m, industrial m2m, m2m communication, remote communication, wireless m2m, remote connectivity, remote access, m2m connectivity, iiot, industrial networking, industrial wireless, m2m iot, smart vending, touchscreen vending, cloud vms, telemeter, vending telemetry, cashless vending, light industrial, commercial, distribution automation, distribution power line monitoring, fault location, fault detection, da monitoring, smart grid, transformer monitoring, intelligent substation, goose messaging, remote machine monitoring, remote secure networks, remote secure networking, secure web based scada , remote diagnostics, remote maintenance, plc programming, intelligent traffic enforcement, ct scanners remote monitoring, mri remote monitoring, healthcare, wireless atm, branch networking, retail, digital signage, wastewater treatment, remote monitoring, industrial automation, automation, industrial transport, inhand, inhand network, inhand networks, Industrial IoT, IIoT, Industrial IoT Manufacturer, Industrial IoT Connectivity, Industrial IoT Products, Industrial IoT Solutions, Industrial IoT Products, industrial IoT Gateway, industrial IoT router, M2M IoT gateway, M2M IoT router, industrial router, Industrial IoT Router/Gateway, industrial IoT Gateway, industrial LTE router, Industrial VPN router, Dual SIM M2M router, Entry level Industrial Router, Cost effective, 3G 4G LTE, WiFi, VPN industrial router for commercial and industrial and M2M/IoT applications, Industrial 3G Router, Industrial 3g router, UMTS router, VPN routerIndustrial 3g router, UMTS router, VPN router, DIN-Rail router, cellular router, Industrial IoT Gateway, Industrial IoT Gateway, M2M gateway, VPN gateway, remote PLC programming, Industrial Cellular Modem, Cellular modem, data terminal unit, 3g modem, Industrial 3G Cellular Modem, 3g modem, industrial cellular modem3g modem, industrial cellular modem, industrial wireless modem, data terminal unit, Android Industrial Computer, Android Industrial Computer, Vending PC, Vending Telemetry, Vending Telemeter, Android Industrial Computer, Android Industrial Computer, Vending PC, Vending Telemetry, Vending Telemeter, Touchscreen & Vending PC, Vending Touchscreen, Vending Telemeter, Vending Telemetry, Vending Computer, Industrial LTE Router, industrial IoT Gateway, industrial LTE router, Industrial VPN router, Dual SIM M2M router, Industrial IoT Router/Gateway, industrial IoT Gateway, industrial LTE router, Industrial VPN router, Dual SIM M2M router, Industrial LTE Router, Industrial LTE router, industrial 4G/3G router, router industrial, cost-effective industrial LTE router, Industrial LTE Router, Industrial LTE router, industrial IoT router, router industrial, cost-effective M2M router, M2M LTE router, Industrial 3G Router , Industrial 3g router, industrial wireless router, VPN router, DIN-Rail router, cellular router, Industrial 3G Router , Industrial 3g router, industrial wireless router, VPN router, DIN-Rail router, cellular router, Distribution Power Line Monitoring System, Overhead Line Monitoring, Distribution Power Line Monitoring, Fault detection & location, Grid Analytics System, Remote Machine Monitoring & Maintenance System, IoT Remote Monitoring, Prognostics and Health Management, Remote connectivity, Remote Maintenance, Smart Vending, smart vending, InHandGo, retrofit, touchscreen vending, cashless vending, cloud VMS, Transformer Monitoring, Transformer Monitoring, substation monitoring, grid LTE router, wireless communication, smart grid, Remote Automation, Remote Automation, Secure remote networks, web SCADA, Remote Diagnostics, Remote PLC programming, Intelligent Traffic Enforcement, Intelligent Traffic Enforcement, wireless networking, cellular router, Wireless ATM Solution, Wireless ATM, ATM Remote Diagnostic, prestashop 多语商城, opencart 外贸商城, 网页设计, 网站建设, 企业建站, 商城网站, 集团网站, 海外网站, 营销网站, 网站推广, 华人网站建设, 华人网站维护, 华人网络兼职, china webdesign, webdesign, seo, joomla web design, 香港網頁設計, 網站建設, 企業建站, 商城網站, 集團網站, 海外網站, 營銷網站, 網站推廣, web design, joomla webdesign, wordpress webdesign, opencart webdesign, magento webdesign, durpal webdesign, vtiger crm, adempiere erp, compiere erp, hosting, domains, vps, email marketing, joomla 网页设计, wordpress 建站, magento 大型外贸商城, durpal 门户网站, seo 网站推广, 网站自然排名, joomla 網站製作, wordpress 定制開發, opencart 維護修改, prestashop 模板修改, magento 培訓實施, durpal 定制修改, seo 營銷推廣, 外鏈收錄排位, joomla, wordpress, opencart, prestashop, magento, durpal, zencart, crm, erp, edm, marketing, joomla template, wordpress themes, magento themes, opencart themes, prestashop themes, 崀山, 崀山科技, 崀山科技全球服务中心, LangShan Technology Global Service Center, LangShan Technology, langshantech, LangShan, china webdesign, 網頁製作, 網頁設計, 企业建站, 企業建站, 在線商城, 營銷網站, 網站推廣, 網站營銷, 排名推廣, 產品推廣, 主機維護, 公司兼職, 網站SEO, joomla seo, wordpress seo, joomla 網站推廣, opencart 網站推廣, prestashop 網站推廣, wordpress 網站推廣, magento 網站推廣, joomla 網站排名, prestashop 網站排名, wordpress 網站排名, opencart 網站排名, prestashop 多语商城, opencart 外贸商城, 网页设计, 网站建设, 企业建站, 商城网站, 集团网站, 海外网站, 营销网站, 网站推广, 华人网站建设, 华人网站维护, 华人网络兼职, china webdesign, webdesign, seo, joomla web design, 香港網頁設計, 網站建設, 企業建站, 商城網站, 集團網站, 海外網站, 營銷網站, 網站推廣, web design, joomla webdesign, wordpress webdesign, opencart webdesign, magento webdesign, durpal webdesign, vtiger crm, adempiere erp, compiere erp, hosting, domains, vps, email marketing, joomla 网页设计, wordpress 建站, magento 大型外贸商城, durpal 门户网站, seo 网站推广, 网站自然排名, joomla 網站製作, wordpress 定制開發, opencart 維護修改, prestashop 模板修改, magento 培訓實施, durpal 定制修改, seo 營銷推廣, 外鏈收錄排位, joomla, wordpress, opencart, prestashop, magento, durpal, zencart, crm, erp, edm, marketing, joomla template, wordpress themes, magento themes, opencart themes, prestashop themes, 崀山, 崀山科技, 崀山科技全球服务中心, LangShan Technology Global Service Center, LangShan Technology, oowebdesign, LangShan, china webdesign, 網頁製作, 網頁設計, 企业建站, 企業建站, 在線商城, 營銷網站, 網站推廣, 網站營銷, 排名推廣, 產品推廣, 主機維護, 公司兼職, 網站SEO, joomla seo, wordpress seo, joomla 網站推廣, opencart 網站推廣, prestashop 網站推廣, wordpress 網站推廣, magento 網站推廣, joomla 網站排名, prestashop 網站排名, wordpress 網站排名, opencart 網站排名, inhandnetworks, InHand Networks Global Leader in Industrial IoT, Global Leader in Industrial IoT, android-computer, iot, industrial iot, industrial internet of things, m2m, industrial m2m, m2m communication, remote communication, wireless m2m, remote connectivity, remote access, m2m connectivity, iiot, industrial networking, industrial wireless, m2m iot, smart vending, touchscreen vending, cloud-vms, telemeter, vending telemetry, cashless vending, light industrial, commercial, distribution automation, distribution power line monitoring, fault location, fault detection, da monitoring, smart grid, transformer monitoring, intelligent substation, goose-messaging-, remotemachine monitoring, remote secure networks, remote secure networking, secure web based scada, remote diagnostics, remote maintenance, plc-programming, intelligent traffic enforcement, ct scanners remote monitoring, mri remote monitoring, healthcare, wireless atm, branch networking, retail, digital signage, wastewater treatment, remote monitoring, industrial automation, automation, industrial transport, inhand, inhand network, inhand networks, InHand Networks - Global Leader in Industrial IoT, Global Leader in Industrial IoT Industrial IoT, IIoT, Industrial IoT Manufacturer, Industrial IoT Connectivity, Industrial IoT Products, Industrial IoT Solutions, Industrial IoT Products, industrial IoT Gateway, industrial IoT router, M2M IoT gateway, M2M IoT router, industrial router, Industrial IoT Router/Gateway, industrial IoT Gateway, industrial LTE router, Industrial VPN router, Dual SIM M2M router, Entry level Industrial Router, Cost effective, 3G 4G LTE, WiFi, VPN industrial router for commercial and industrial and M2M/IoT applications, Industrial 3G Router, Industrial 3g router, UMTS router, VPN routerIndustrial 3g router, UMTS router, VPN router, DIN-Rail router, cellular router, Industrial IoT Gateway, Industrial IoT Gateway, M2M gateway, VPN gateway, remote PLC programming, Industrial Cellular Modem, Cellular modem, data terminal unit, 3g modem, Industrial 3G Cellular Modem, 3g modem, industrial cellular modem3g modem, industrial cellular modem, industrial wireless modem, data terminal unit, Android Industrial Computer, Android Industrial Computer, Vending PC, Vending Telemetry, Vending Telemeter, Android Industrial Computer, Android Industrial Computer, Vending PC, Vending Telemetry, Vending Telemeter, Touchscreen & Vending PC, Vending Touchscreen, Vending Telemeter, Vending Telemetry, Vending Computer, Industrial LTE Router, industrial IoT Gateway, industrial LTE router, Industrial VPN router, Dual SIM M2M router, Industrial IoT Router/Gateway, industrial IoT Gateway, industrial LTE router, Industrial VPN router, Dual SIM M2M router, Industrial LTE Router, Industrial LTE router, industrial 4G/3G router, router industrial, cost-effective industrial LTE router, Industrial LTE Router, Industrial LTE router, industrial IoT router, router industrial, cost-effective M2M router, M2M LTE router, Industrial 3G Router , Industrial 3g router, industrial wireless router, VPN router, DIN-Rail router, cellular router, Industrial 3G Router , Industrial 3g router, industrial wireless router, VPN router, DIN-Rail router, cellular router, Distribution Power Line Monitoring System, Overhead Line Monitoring, Distribution Power Line Monitoring, Fault detection & location, Grid Analytics System, Remote Machine Monitoring & Maintenance System, IoT Remote Monitoring, Prognostics and Health Management, Remote connectivity, Remote Maintenance, Smart Vending, smart vending, InHandGo, retrofit, touchscreen vending, cashless vending, cloud VMS, Transformer Monitoring, Transformer Monitoring, substation monitoring, grid LTE router, wireless communication, smart grid, Remote Automation, Remote Automation, Secure remote networks, web SCADA, Remote Diagnostics, Remote PLC programming, Intelligent Traffic Enforcement, Intelligent Traffic Enforcement, wireless networking, cellular router, Wireless ATM Solution, Wireless ATM, ATM Remote Diagnostic, prestashop 多语商城, opencart 外贸商城, 网页设计, 网站建设, 企业建站, 商城网站, 集团网站, 海外网站, 营销网站, 网站推广, 华人网站建设, 华人网站维护, 华人网络兼职, china webdesign, webdesign, seo, joomla web design, 香港網頁設計, 網站建設, 企業建站, 商城網站, 集團網站, 海外網站, 營銷網站, 網站推廣, web design, joomla webdesign, wordpress webdesign, opencart webdesign, magento webdesign, durpal webdesign, vtiger crm, adempiere erp, compiere erp, hosting, domains, vps, email marketing, joomla 网页设计, wordpress 建站, magento 大型外贸商城, durpal 门户网站, seo 网站推广, 网站自然排名, joomla 網站製作, wordpress 定制開發, opencart 維護修改, prestashop 模板修改, magento 培訓實施, durpal 定制修改, seo 營銷推廣, 外鏈收錄排位, joomla, wordpress, opencart, prestashop, magento, durpal, zencart, crm, erp, edm, marketing, joomla template, wordpress themes, magento themes, opencart themes, prestashop themes, 崀山, 崀山科技, 崀山科技全球服务中心, LangShan Technology Global Service Center, LangShan Technology, langshantech, LangShan, china webdesign, 網頁製作, 網頁設計, 企业建站, 企業建站, 在線商城, 營銷網站, 網站推廣, 網站營銷, 排名推廣, 產品推廣, 主機維護, 公司兼職, 網站SEO, joomla seo, wordpress seo, joomla 網站推廣, opencart 網站推廣, prestashop 網站推廣, wordpress 網站推廣, magento 網站推廣, joomla 網站排名, prestashop 網站排名, wordpress 網站排名, opencart 網站排名, prestashop 多语商城, opencart 外贸商城, 网页设计, 网站建设, 企业建站, 商城网站, 集团网站, 海外网站, 营销网站, 网站推广, 华人网站建设, 华人网站维护, 华人网络兼职, china webdesign, webdesign, seo, joomla web design, 香港網頁設計, 網站建設, 企業建站, 商城網站, 集團網站, 海外網站, 營銷網站, 網站推廣, web design, joomla webdesign, wordpress webdesign, opencart webdesign, magento webdesign, durpal webdesign, vtiger crm, adempiere erp, compiere erp, hosting, domains, vps, email marketing, joomla 网页设计, wordpress 建站, magento 大型外贸商城, durpal 门户网站, seo 网站推广, 网站自然排名, joomla 網站製作, wordpress 定制開發, opencart 維護修改, prestashop 模板修改, magento 培訓實施, durpal 定制修改, seo 營銷推廣, 外鏈收錄排位, joomla, wordpress, opencart, prestashop, magento, durpal, zencart, crm, erp, edm, marketing, joomla template, wordpress themes, magento themes, opencart themes, prestashop themes, 崀山, 崀山科技, 崀山科技全球服务中心, LangShan Technology Global Service Center, LangShan Technology, oowebdesign, LangShan, china webdesign, 網頁製作, 網頁設計, 企业建站, 企業建站, 在線商城, 營銷網站, 網站推廣, 網站營銷, 排名推廣, 產品推廣, 主機維護, 公司兼職, 網站SEO, joomla seo, wordpress seo, joomla 網站推廣, opencart 網站推廣, prestashop 網站推廣, wordpress 網站推廣, magento 網站推廣, joomla 網站排名, prestashop 網站排名, wordpress 網站排名, opencart 網站排名, inhandnetworks, InHand Networks Global Leader in Industrial IoT, Global Leader in Industrial IoT, android-computer, iot, industrial iot, industrial internet of things, m2m, industrial m2m, m2m communication, remote communication, wireless m2m, remote connectivity, remote access, m2m connectivity, iiot, industrial networking, industrial wireless, m2m iot, smart vending, touchscreen vending, cloud-vms, telemeter, vending telemetry, cashless vending, light industrial, commercial, distribution automation, distribution power line monitoring, fault location, fault detection, da monitoring, smart grid, transformer monitoring, intelligent substation, goose-messaging-, remotemachine monitoring, remote secure networks, remote secure networking, secure web based scada, remote diagnostics, remote maintenance, plc-programming, intelligent traffic enforcement, ct scanners remote monitoring, mri remote monitoring, healthcare, wireless atm, branch networking, retail, digital signage, wastewater treatment, remote monitoring, industrial automation, automation, industrial transport, inhand, inhand network, inhand networks, InHand Networks - Global Leader in Industrial IoT, Global Leader in Industrial IoT